The vaccines as they are would have been perfectly fine if the wild type of SARS-Cov2 were everything we had to deal with. At least you seem to be referring to that because of the level of efficacy you mention. Unfortunately the pesky Delta variant appeared and threw a spanner in our works. Now there is the Omicron variant which seems to be even more infectious.

As much as I understand that people would prefer if the world were simple and solutions obvious but it just not is this way. It's messy and things change and that means that yesteryear's statements just might no longer be true. We need to deal with that and please do not make things more complicated than they are anyways already.

Versus the variants available at the time, yes. Unfortunately, the people running the studies couldn't get the budget for a time machine to see what would be happening in late 2021.

Note that the possibility of future variants was certainly raised at the time; it was never any secret that this was an evolving situation.

It initially was 90%+ protection.