More immediately, high-tech wizardry is threatening to replace service with a smile. In Los Angeles, Westin's Cyber Suite, has a computerised butler-in-a-box which uses speech recognition to control lighting, curtains, temperature, TV, entertainment centre and all appliances. Guests can call the "butler" from the poolside or the hotel restaurant and have it draw their bath, to the desired temperature, before returning to their room.
Plenty of travellers are becoming more self-sufficient, as if they prefer being left alone without old levels of intrusive service. Hyatt's vice-president, Craig Parsons, says that future hotel rooms will allow frenetic guests to serve themselves how and when they want. He foresees luggage being checked in direct from airport to room and back. Guests will bypass registration at the front desk, going straight to their rooms where their credit cards will act as keys and automatically advise the hotel computer of their arrival.
All services will be reachable on a single mobile phone - guests will be able to communicate with home and office, access their bank accounts, get local directions and sightseeing information, make tour reservations and surf the internet from in-room televisions through a single communication system.
To avoid the possibility of travellers being disappointed when they open their hotel room door, they will be able to pre-customise their room. To some extent you can already do this. When making a reservation at California's Claremont Resort, for example, rooms can be stocked with the guest's favourite beverages and snacks; preferred newspapers will be delivered and convenient cleaning times arranged. And the hotel will remember the choices for every subsequent visit.
Andrew McCulloch, head of research and development for Hilton International, predicts that rooms will become fully interactive so that guests can create preferred surroundings and preview restaurant settings and menus, see room service as they order and view the pool (or their family left at home) from their mobile communications system. Air jets pointing at the bed will enable guests to design their own "ergonomic sleeping experience". Keys will be replaced by thumb-print cards or a scan of the guest's retina.
With only the communications system for company, life for the road warrior will be lonelier. There will be no popping down to the business centre; computer equipment centres will be in every room. The communal health centre workout will become solitary, with in-room mini spas. Designer Brent Severin's Room 2000 concept for Westin includes a multi-exerciser, a spa with hydro-massage and a whirlpool in every room. Jet lag will be cured by over-bed adjustable light boards releasing melatonin.
Even restaurants will be phased out or changed from their present formality. They will be replaced by bars serving snacks or outside caterers connected by computer who will send in whatever the guest orders. As for room service, Westin has already devised a Silent Server which will replenish the mini-bar, provide breakfast and collect and deliver laundry, linen and other amenities through a private hole-in-the-wall cupboard accessed by unseen staff.
Nor will there be so much need to go out shopping. Hotels are rethinking mini-bar stocks, gradually turning them into general purpose travellers' "shops". London's Mayfair Intercontinental sells condoms, tampons and cures for colds and hangovers in its mini-bars. For the busy visitor they include souvenirs - such as toy double-decker buses and teddy bears - disposable cameras, computer discs and laptop adapters.
Still, there will be fun to be had by playing with the bedroom furniture and the bathroom. Furniture, to appeal to both the business and the elderly leisure traveller, will be multi-purpose. Using touch control screens, beds will adjust from hard to soft, become daytime sofas or disappear into the wall for business meetings while desks transform to dining or games tables. The traditional dresser or bureau will become part of an all-purpose media wall according to Hyatt.
Coming clean will also be a lot more fun. Glass screens separating bath from bed areas will defuse sun glare and reduce fly light, stopping the fading and discolouring of the decor. Hilton thinks bathroom walls will go entirely, replaced by opaque screens that can be electronically activated when privacy is required. Guests will no longer need a degree in engineering to operate the shower; they will just talk to the shower to control temperature and pressure. Self-cleaning baths are already starting to appear. After the water drains out of a tub at Le Mirador in Switzerland it automatically spits up water through spray jets to clean itself with an alarming hissing and rumbling.
Hong Kong's Peninsula hotel already has high-tech devices powered by no fewer than 90 electrical outlets in each room. Couples will appreciate bedside sockets, which allow one to enjoy radio or TV without disturbing the other. Touch panels show weather reports; shoe boxes automatically signal the attendant to come and clean shoes; phones with world time clocks automatically set themselves to guests' home time on check-in and display world time and public holidays.
In the Pen's bathrooms, lights can be mood set and a hands-free phone automatically mutes the radio or TV during calls while bathing or shaving and restores the programme on hanging up. The phone also mutes the background sound of running water and compensates for that cavernous bathroom sound.
And there is a TV set in the wall at the end of the bath with a remote control panel close to the wallower's hand. Hotels of the future will be great places for catching up on the latest TV and movies. Those waiting for friends in the lobby at the Lindner Hotel in Frankfurt will be entertained by a TV monitor wall with 12 screens and plug-in headsets.
Hotels will not be just for business or holiday visits; in some cases they will be for life. The rich have long used hotels as surrogate homes but now, in the US at least, they have started buying into the hotel, gaining special privileges and dictating standards. So much for a change of scene.
For further details of the hotels mentioned, contact: Westin Century Plaza (tel: 0800 282565); Hyatt (tel: 0345 581666); Mayfair Intercontinental (tel: 0171-629 7777); Le Mirador, Switzerland and Peninsula, Hong Kong can be booked through Leading Hotels of the World (tel: 0800 181123); Lindner Hotel, Frankfurt (tel: 0037 211 59 97 310).