Startups usually have no choice, they cannot afford A players. There are businesses which do hire A-players such as OpenAI, Jane Street, Netflix, etc. but A players require A compensation.
>>__turb+(OP)
And a lot of A players are unique snowflakes so they have to be compatible with other unique snowflakes so it can be hard to fill the gaps. You need a few Bs who are moldable to fill gaps