To me this is just incredible. As an old timer who learned the ropes in the late eighties it never crossed my mind (what with computers always getting faster) that we would once again face the situation that developers can't run their software locally. It's like a bloody throwback to the sixties and the days of punchcards and timesharing systems. Thanks but no thanks!
It's such a friction factor that all other benefits of the platform get overshadowed by this. It's the same reason I'm vehemently opposed to my team using AWS Lambdas for anything non-trivial. And no, SAM is not the answer here.