In my experience, yes.

The support I have received fromAWS has been literally stellar over anyone I've ever worked with.

Even now, my previous rep got promoted and moved on from account mgmt but if I send him a one-off question he gets it answered and taken care of immediately.

I have literally out of hundreds of calls and meetings with aws been disappointed with one call. That was when I accidentally changed my root account email address and I couldn't recall which email I had set it to, so I clicked the "contact customer service" link from the forgot password page and it connected me with the "Amazon.com" (shopping) customer service agent who apparently had no fucking clue what aws was.

Not completely the same, but I meet with regional aws staff a few times a year including product managers.

AWS enterprise customers get case managers as points of escalation and this is a generally accepted strategy for almost everyone in enterprise to the extent that I believe customers would be very concerned if this type of customer outreach model was not in place. This does not necessarily mean that this is the same thing as a services style engagement manager either.

Note that this does not mean that I think it's optimal, but I do mean that a vast majority of enterprises have a form of group-think culturally that makes this approach something that's demanded as a standard service offering that is no different than developers expecting APIs from a hosted service.

Yes, of course. If you are a company, you know your rep.