NBA draft combine is not the premier talent evaluation for NBA prospects. Las Vegas, Phoenix, Chicago, and Norfolk are the big bball events. I really have no idea why and NBA prospect would waste their time at a combine.
No way to really gauge shooting ability or defensive skills in terms of shot blocking by measuring how high you jump or how fast you run. Its just not the same as with the NFL.
This isn't really true. Norfolk, for instance, is only for college seniors, and most of the kids who show up are trying to show for a summer league invite. The combine is the premier place for measurements, physicals, and meeting with team officials.
It's not unprecedented for top prospects to participate marginally, but it's unusual for them to not show up and say hello. They're represented by the same agent, and it's a bit of a power play in my opinion. I don't think it will hurt Parker at all, and it might not hurt Embiid if he'll look better in four weeks than he does now. That said, I think Embiid is playing with fire -- the expectation is he won't go to a physical for more than the top 2 teams. If they don't take him, does whomever pick 3rd think that teams 1 and 2 just like Parker and Wiggins more (possible), or that there is something to avoid in his medical reports? It could definitely cause him to fall if a few teams don't want to take a risk on something that they haven't seen, but that the teams who have seen it have passed on.