I can see no diminution of interest in classical music in the general population. Indeed, I venture to say that both knowledge and private playing of classical music are much more common than when I was a child. In those days people interested in classical music were frequently ridiculed as sissies or snobs. I just don't see this happening any more; classical music is now an acceptable and laudable field of interest.
It may well be that a professional saturation point is being reached as far as orchestras, operatic companies, pianists and the like are concerned. However, at the amateur level and in the home, modern technology and the internet have brought any music, anywhere in the world, within the hearing of all. Many sites allow sampling of CD tracks and even relatively little known works can be ordered at once and delivered within a week. Large stores have bin upon bin of recordings of classical works and these CDs appear on the shelves in people's lounges with a frequency quite different to the sparse and specialised LP collections of minority classical enthusiasts of my childhood.
Classical music will always be loved and, as I see it, its audience is growing and crossing international and cultural boundaries in ways impossible to envisage fifty years ago. Simultaneously, we have non-European classical music of Asia and other places influencing Western musical thought via the same channels.
So no, I cannot agree that the situation with regard to classical music is worsening. The most musical nation is not that which spends the most on superstars, concerts, operas and spectaculars. Surely it is that in which Beethoven, Chopin, and the rest, including the modern masters, are frequent and welcome guests in the home - either via performance or through recordings. In this sense I can really see little to worry about.
You may be quite right as far as the economic and social modes of transmission of classical music are concerned. These are changing, as are all modes of artistic communication in the modern world. But I conjecture that while some of the old modes of performance and education may slowly disintegrate, the underlying power of classical music in general consciousness will always live as long as we have ears and brains - and it's the underlying power that counts in the end.