Apple is in the end a hardware company with a side in services, which isn't a good thing in today's tariff war landscape. This is causing Apple to have a murky outlook. While I don't think anyone is claiming Apple is go bankrupt and close up shop, they might be in for a rough future.
IBM was the biggest computer manufacturer until it wasn't, Sega was one of the biggest makers of gaming hardware (Genesis) until it wasn't. Blackberry was THE company for smartphones, until it wasn't. All of these companies still exist today but because they couldn't adapt fast enough, they are now a shell of themselves. I think this is the worry about Apple. Apple has tried for years to make more from services income, but aside from the App Store, they haven't done very well. And the App Store is heavily tied to their hardware, which leads back to the original issue.
As for their amounts of cash and investments, their investments haven't been rewarding. The Vision Pro is still considered a failure, the Apple Car was canceled, and Apple Intelligence hasn't been helping their bottom line either as it isn't holding up to it's promise. Besides those three, what else has Apple invested in and gotten their moneys worth in the last 5 years? The Apple Watch is 10 years old, the airpods are 9 years old, and they have the same issues as iPhones with their being physical devices that can be harmed with these tariff wars. Every major income source for Apple is affected by tariffs, and that will hurt it's future, in the near short term and possibly long term.