I agree that writing because you
have to, to make a living, is unlikely to be fun. There's too much pressure to succeed all the time, because if your next book doesn't make a decent profit for the publishers they're likely to drop you. That's bad, because not only is finding a publisher difficult at any time, it's likely to be even tougher if they know you're already been dropped as a poor seller.
These days, very, very few writers make a decent living out of their writing. The great majority, including many who are well-known and enjoy consistently good sales, need some other source of income to pay the bills.
So my advice is: write for fun. If you enjoy it (as I do) that's great, and worth doing for its own sake. If you manage to sell anything to anybody, that's brilliant - but keep the day job.
This article should give you food for thought about how difficult the publishing business is even for a moderately successful author. You might also want to read
this