C#, a 21 year old programming language which consistently makes it into the top 6 programming languages by popularity in all methodologies of measuring, "launched and soon sank with little trace"? That's an interesting take.
is that saying anything if microsoft is basically eternal? what, you think the company that makes excel and windows is gonna go out of business any time soon?
The usual route is becoming irrelevant. Windos failed to achieve relevance in mobile and cloud, and desktops become less relevant every day. If at some point you don't need MS to do excel anymore, MS becomes irrelevant there, too.
There are still Burroughs, Univac, and Honeywell computer companies, in a way, but they attract no attention.
We can be pretty confident, anyway, that it won't outlive Microsoft.