I find this vesting schedule being brought up strange (I see this somewhat frequently). On hiring you get a signing bonus, in my case the value of this bonus made my comp almost flat for those 4 years if the share price remained constant. If anything, this additional cash, which was given each month, was a positive when starting out. Vesting is inherently lumpy, and makes managing cash flow a bit more tricky. I also received base increases despite a very large stock price increase.

On 401k, I'm not in the US so cannot comment.

Your other points around timelines and pages don't match my experience, but I assume that in such a large company they do exist. I have certainly heard of a team where the high sev counts were similar to the numbers you give. Perhaps I am lucky to have missed them, or others are unlucky to have experienced them.