I mean, yes, obviously, it is possible to be both successful and happy. (And here I'm defining "success" from an artistic/critical standpoint, not commercial, which brings about its own set of issues.) A lot of great music, literature and visual art has come from artists in positive mindsets. So this shouldn't even be a choice worth discussing.
Right?
Maybe. Look, it's not an entirely uncommon idea that artists often produce their best work when they're miserable, depressed, paranoid, jealous, etc, place your favorite descriptor of an unhappy life here. Let's pretend for a second that this has a kernel of truth - those with an axe to grind probably have something more interesting to say than those who are just hanging out, right? If so, it can create a problem for an artist's followers and fans. Do you wish your favorite artist the best in life, or do you want the quality of their work to remain as high as possible, no matter the cost?
Quick example: One of my favorite bands is The National. Lord knows I can't recommend these guys enough. They write some of the most beautifully depressing music I've ever heard. And they're perfectly allowed to write happier songs, too - a lot of their newer, comparatively more positive stuff is good, but I always feel like they're better at illustrating a whiskey-soaked, heartbroken 3am comedown than describing the best way to make their girlfriend laugh. (Maybe it's me.)
Some friends and I went to see their show several weeks ago, and we were blown away by their performance and musicianship as usual. But we also noticed singer Matt Berninger seemed to be having a tougher time of it than usual. Struggling with some of his more personal lyrics. Nervous, abortive physical maneuvers around the stage. Lots of screaming. It was the kind of intensely awesome performance we hadn't seen out of him since maybe '06. And we (arbitrarily) decided that he must have broken up with his girlfriend. Which in turn made us think "cool, now he's going to start writing darker music again."
Which is a pretty fucked up thing to think, leap of logic or not. As an artist, your fans are bound to gravitate toward certain works, and what they might expect from you is not necessarily what you want to provide (our frequent concert shout-outs requesting one of the most depressing songs ever written always go unheeded, sadly). It's a divide that comes with the territory. But it's another thing entirely for fans to desire a quality of life for the artist.
Ideally, yes, we would like our artists to be happy/comfortable/rich and also to continue producing excellent works of art. But if you have to choose one result over the other, what would it be? Is it even a choice where, after having made it, we could still feel comfortable with ourselves? It's a burden I wouldn't want to have to bear, though it's a choice I feel I sometimes unconsciously make about artists I genuinely respect.
And, if someday my writing finds a fanbase and some level of popularity, it's also something that many strangers may be quietly theorizing about me. Which is pretty fucking creepy.