Sometimes it’s best to stick to what you know while accepting that the market will shrink

I argue it's always best to do that. A company dying doesn't mean it failed, it just means it fulfilled its purpose. Investors should leave, not because the company is poorly run, but because other technologies are more promising. These companies shouldn't go bankrupt, but merely scale back operations and perhaps merge with other companies to maintain economies of scale.

I honestly really don't like companies that try to do multiple things, because they tend to fail in spectacular ways. Do what you're good at, fill your niche as best you can, and only expand to things directly adjacent to your core competency. If the CEO sees another market that they can capture, then perhaps the CEO should leave and go start that business, not expand the current business into that market.