Different travelers have different mindsets-- and travel patterns. Some do as mentioned up-thread and "focus on status at other brands". Others of us use the LT status we've earned because it's valuable. I'm glad I earned UA MM years ago, for example, because shortly after that my business travel dropped significantly such that maintaining even silver status on any legacy airline would be hard to swing. I've continued flying UA as my main long-haul airline because the benefits of that LT gold status are meaningful.

Of course, that only applies if the benefits are meaningful. I'm staying with Hilton more than Marriott right now, despite holding LT Titanium status in Marriott's Bonvoy program, because it's just not worth it. Their hotels are frequently overpriced (vs. comparable HH or IHG properties) and it's not worth it for the rare chance of getting a begrudging small upgrade.