Imo "loaded with cash" now doesn't mean what it used to, unless you have massive name recognition like Hillary or Biden.
I also don't think basic optics is a big enough factor here. He needs to have a lot more happen. He plays the game too carefully, trying to not alienate anybody, for him to stand out himself. He hasn't seen rising poll numbers for the past 4-5 months, while Warren moves up, Kamala rises and falls, and Biden gradually slips. That can't be ignored. And when it comes down to it, I don't think the DNC folks will ignore his poor general election polling even if their instinct is that he's electable.
This could be a unique election, but Nate Silver even pointed out that candidates polling at <5% at this point in the race have only won 2% of the time. Buttigieg's averaging about 5% right now. Yes there's still time, but his breakout period should've already happened and he failed to truly claim a significant base. Banking on future dropouts' supporters maybe coming to you as an alternative isn't a great strategy if you're not already winning enough people over. Without some huge event, big shift in strategy, or huge debate performance (i.e. Kamala's first debate) beyond just doing "good", he's going to be running a doomed campaign into Iowa.