I don't think its just being "wimpy". I'm sure they've had a lot of internal discussion about making an addition like Skubal, but believe that the way for them to maximize their chances at a WS is to be a very, very good team every year vs. moving pieces that they think will help them compete for the next 5+ years to increase their chances at a 2026 title from 9 to 14% or whatever.
I think this is defensible. You don't necessarily need a super-team to win. The Braves weren't in 2021. The Rangers weren't in 2023. The Jays weren't last year. You do need to make the playoffs though.
I think there are also financial reasons that make sense as well. The Brewers are legitimately a small market team. The ideal model for them in the current format is to be competitive every year. This becomes a lot harder to accomplish if they're cashing blue chip pieces for rentals.