> Why not?

Because money is finite? Not every research grant gets funded. So let's start with the most promising ones?

Funding vaccines that are not meeting standards should be dropped so that standards can be met. These companies don't need money for R&D, they have enough and can recoup it if they create a product that the market wants.

There are different levels of research. Right not Adrenovirus vaccines need to go back to the lab and figure out this clotting issue. Maybe they can, maybe they can't, either way this is a basic research question that needs only a tiny amount of research money. More importantly, that money needs to be spread over a few years.

Most of the vast amounts of research funding given isn't really research, it is scaling up production - a much harder problem that needs much more money. Since we now know of some issues (that would be very hard to find before a large scale roll out - lets not put undeserved fault on anyone here) the labs can focus on them.