I somewhat disagree that everything should be retroactive. We might be able to get some smaller scaled projects coming, but not attract any bigger, more complicated projects.
Sure it will help fuel the people already here, but working without a a runway is risky in itself.
I am okay with gambling on some rookies in order to help bring new people into the ecosystem and they can be evaluated on a case by case basis.
Grant farming is a big issue across web3, but there have been plenty of existing ecosystem projects that have received grants that are still here and building. I feel like when it comes to this topic we often focus on the bad grants and ignore the good ones.