There aren't enough proteins in the vaccine that the virus cannot adapt around the vaccine.

I'm not a virologist. More of a evolutionary science buff.

The virus will adapt past the conditions set for it. The genetic variety of the virus is immense now. This is the key factor to why it won't work. We're only slowing it down. Which is not entirely bad, but the vaccine is ultimately near useless. People with severe health conditions will probably still die.

The vaccine contains several proteins but not the whole virus. We've actually created the conditions for adaption. The vaccinated individuals will kill the old virus but a mutated variety will always propagate without herd immunity.

According to what I know about adaption anyway.