They could have adapted - Onkyo was slow to adopt new digital interfaces, smartphone connections, networking, and other de rigeur technologies.
Perhaps you could be right. I doubt they could retain their reputation for audio excellence in such an environment, though. People who want to listen to audio on earbuds or, worse yet, a phone or tablet’s speakers, do not really care about the quality of sound they are getting. They certainly are not going to pay for it. It’s really a different market.
In any event, it’s a good reason to take care of good equipment. Don’t take the ability to replace that amplifier for granted.