I dont mind bandwagon fans. Imo there is nothing wrong with the term as that is perfectly descriptive of how some people operate... they only follow through the thick and not through the thin.I suspect this is accurate. People want to be entertained. Winning is entertaining, losing isn't. Most fans just want to watch a good, competitive, entertaining product, and they'll return once we're back to providing it. It's only a relatively small subset of fans who pin everything on winning the title; the "bandwagon" fans will be happy to watch 82 games of good regular season basketball, regardless of how far the team advances in the playoffs.
I would also say that I find the term "bandwagon fan" and how it's used to be intentionally pejorative; as if prioritizing entertainment quality is somehow a character flaw. It strikes me as an entirely reasonable way to consume an entertainment product.
But they shouldn't be moralized for doing that. They are just following one of the most basic laws of business... you put out a bad product and you are gonna lose consumers. And by doing so they actually incentivize the owners to put out a good product, so looking from that perspective they are "better fans" than those who buy season tickets and merch regardless of how the team does.