Everyone can be replaced, even the songwriting star front man, Genesis, Pink Floyd for example?
It's also easy to replace a star band member, Allan Clarke, Paul Jones, Clapton, Peter Green, Moon and Entwistle and Brian Jones.
They decided they couldn't replace John Bonham, but in the end Led Zep did just that.
At the other end of the scale, we've just fired our drummer, of about the last 8 years. He seemed to think his place was guaranteed and he gradually stopped trying.
To get back on topic, if your playing is a hobby then you'll stop and start as you feel like it. Guys like Blue, and me, play because it's in out blood. We'll not stop playing without a fight.