Short-sighted arts policy plus a shortfall of cash are the two factors most frequently blamed. But what if the orchestra itself is no longer a valid institution? Has it changed from being music's ultimate machine to just another period instrument?
Exponents of authenticity and historical performance would certainly argue it has. The symphony orchestra, they say, is a classical creation, beefed up by Romantics and kitted out with 20th-century embellishments. Following a Darwinian evolution, it peaked in sophistication some time before the First World War, chiefly through the expertise of Gustav Mahler and Richard Strauss.
Thereafter, composers tried to dissolve, enhance and divide this monolith. Stravinsky shattered its identity into smaller groupings, but returned to the full orchestra for his big symphonic statements. Radicals such as Edgard Varese broke with it altogether. Attempts in the 1950s and Sixties to rearrange it or combine it with electronics have proved transient.
While the orchestra has become stuck in the rut of its own repertoire, the success of period ensembles and the cult of authenticity over the past two decades have cast doubts on how much of that repertoire the big bands rightly own. This shift in public taste has come about largely through the success of the recording companies in developing new market areas, whether Albinoni concertos, Victorian concert overtures or Steve Reich.
And here's the irony. For though the sanctity of the symphony orchestra is now threatened by the musical plurality encouraged by recording technology, those orchestras were the first to jump on the recording bandwagon earlier this century and to promote the record rather than the live performance as the musical ideal. What we now think of as the typical orchestral sound is in fact the super-efficient timbre developed by Toscanini, Stokowski and others to sell their reputations on disc: the NBC's Pathetique versus the New York Philharmonic's, and so on.
The aim was to offer perfection, performances you could hear a hundred times without boredom. And all too often this left no room for mistakes or idiosyncrasies, and produced a sound distorted to meet the needs of the studio rather than those of the composer.
In reaction to this, one pioneer of popular classical recordings, John Boyden, has returned to live performance. The point of his New Queen's Hall Orchestra is to play with French rather than German horns (the latter were introduced in the 1920s for a fuller, safer sound), with narrow-bore woodwind giving a more precise tone, and with gut rather than metal strings. The group offers ear-catching performances of Brahms, Elgar and Vaughan Williams, sounding as they would have done before the advent of the studio orchestra. It has also, avoided a permanent venue, conductor and organisation - the trap into which the established orchestras have fallen. And not just the established orchestras: the London Sinfonietta, founded in 1968 with a radical agenda to play 20th-century works for non-standard line-ups, now has the expectations of a big orchestra, plus administration and a place on the funding merry-go-round.
A Sinfonietta commission remains an honour for composers. But increasingly they prefer to create their own ensembles. Michael Nyman and Graham Fitkin have enjoyed success with groups tailored to suit their musical needs. The CD-buying public likes the resulting diversity and approachability. And the overlap of pop and ethnic musics, plus electronic media, continue to marginalise the symphony orchestra at the edge of the arts pitch.
There's no clearer evidence for this turnaround than in schools. Composing is at the heart of the national curriculum, but expressed in a plurality of forms from improvisation to pop and ethnic music.
Cynics respond that chaos is a good thing. Let the arts world conform to supply and demand; something leaner and fitter will emerge. The argument for funding a 'super orchestra' is the pinnacle of this fallacy, as if the LSO and others do not supply this already.
Yet positive things are still happening. Earlier this month a new orchestra, the Britten Sinfonia, made its London debut. The choice of name is significant: Benjamin Britten knew the importance of both amateur and professional music-making, and of musical life in the community. The rancorous squabbling among today's top musicians would have appalled him.
As for future policy, why not shift resources to where music really belongs? That means funding amateur music-making, the world-class jazz and classical youth orchestras that have withered on the vine after a decade of cuts, hard-pressed music clubs and local government schemes that support professionals, and the new vocational modes of music opened up in schools, of whatever style and provenance.
The orchestra can be revived, as long as people still want to share its repertoire through playing and listening. Young composers such as Steve Martland have already grasped the importance of taking classical music out of concert halls and into community centres and schools. In addition, new forms are more likely to arise from enthusiasts experimenting than from another batch of Arts Council reports.
An informed and committed public, supported by a long-term investment in amateur skills, could be one way of ensuring musically literate audiences in years to come. It might even guarantee that nobody would again tolerate the kind of official neglect that made for the present shambles.
A longer version of this article appears in this week's 'New Statesman and Society'.