I would like to think that the reason I play is selfishly for myself more than anything. I strive to better myself in the things I enjoy, and the piano just happens to be one of them things.
I am a very nervous performer even much so that the GF could be in the bath, upstairs not paying attention and hear me play a piece perfectly. Soon as she comes down to actively listen, it often falls apart and so for me, playing for others is not something I particularly enjoy.
But i'd say the things I practice in life are influenced by various factors. The piano I practice for myself, Computer programming I practice for my job, going to the gym I do to keep in shape and healthy (physically attractive to the GF!)
It's very tough to give every aspect of our interests equal attention and so for me in particular, I find I go phrases, for a couple of months I may spend hours and hours at the piano, then drop it for a month and concentrate on my fitness, maybe balance some piano with my career over the next couple of months and so on.
So being the last person on earth here's my thought process.
My interests are now massively influenced by different things. No longer would I need to concern myself with a career, no longer would I concern myself as much with fitness etc etc. Take away a lot of factors and see what i'm left with.
The piano would be on that agenda throughout, as it's one of the few things I honestly think I do just for myself. So that would never be given up and always be something I'd come back to.
But ultimately I would also have to consider the long term goals, and as this is a hypothetical situation, i'm going to be quite "out there" and say i'd start getting my head down in researching AI computing and start getting some company to stop myself going MAD!!