Predicting the future is always fraught, particularly in times of upheaval, but here are some of my thoughts on the evolution of classical music.
1. Smaller ensembles like string quartets will survive better
A few years ago, I saw a job posting for a string quartet position in rural Canada. I inquired about the job, and the response was very interesting. Basically, the quartet provided classical music and music education to people in this rural area of Canada that would otherwise not have assess to concerts of any kind. Although I did not end up taking the audition, I thought at the time what a great idea it was. One of the difficulties small regional orchestras face is that they pay their musicians enough to convince professional musicians to move to their small town and settle in. But funding a full-time string quartet or brass quintet would be a much different story. Small towns and rural areas have much lower rent for struggling musicians, and often they have a high need for both entertainment and music education. I wish more towns would consider funding a full-time small ensemble instead of a part-time drive through orchestra.
2. Musicians need to learn how to freelance effectively
Most of my training as a young musician involved "Learn this piece. Now this piece. Practice for auditions, even though you'll be competing against hundreds of other people just like you, and even if you win your dream job there's a possibility your orchestra will file for bankruptcy and you'll be back out auditioning again in a few years." That's not a viable career path for most young musicians anymore. Schools need to teach the skills most students actually need--how to network, how to promote yourself, how to survive as a freelancer. How to be a good teacher. Otherwise, you'll end up with miserable graduates who struggle to pay back their ridiculously huge loans until they give up.
3. Classical music (or Art music) will have hundreds of small niches
This has been going on for a while now. While there used to be large organizations that promoted a set of "standard" classical pieces, usually large-scale romantic works, classical music has dramatically expanded into ancient music or baroque ensembles, or new music ensembles, and many musicians actively seek out new music. Many integrate jazz or folk music into their repertoire. I think this will continue as we go forward. Musicians will seek out the music that inspires them, and either develop a unique style or continually explore the immense variety and depth of music available to us today. One of the most remarkable things about living in the modern world is how much access we have to music--we can listen to music from all over the world, and from many different time periods. That's an exciting development, but one that can feel overwhelming sometimes.