Yes, it seems like s th changed, a lot of people who supported Schumer before, like bernie Sanders, have withdrawn their support. Hollen seems to be ready to run now and I am hapy about it if he actually has the support. At least it seems like there is an actual attack on Schumer now with a clear spearhead.
I think it means that it is bad optics for Van Hollen if he outrights starts a run against Schumer without a strong show of support for it. He does not want to seem like someone who splits the party by his run if he has not enough steam. But if a lot fo Senators call for a run and call for Schumer to resign, he would be ready to be the candidate that COULD replace him if Schumer does not manage to convince them.