They are, for what? Let's see:Well, like I said, I don't think the 800+ extra pins are there for no reason. Doesn't the "Threadripper" socket have something like 4000 puns?
If I wanted to be a a**hole, (which I often do), I'd say AMD could have shoehorned that into an AM-5 board too.
In any case, "hate on".
AM3 939 pins
AM4 1331 pins (+392 pins)
AM5 1718 "pins" (+387 pins)
LGA1151 1151 "pins"
LGA1700 1700 "pins" (+549 "pins")
LGA2251 2251 "pins (+551 "pins")
You may argue that LG1700 must support both DDR4 and DDR5. However LGA2251 will drop DDR4 support pretty sure so increasing pin count same amount that LGA1700 did, invalidates that claim. Most extra pins are most probably for no reason.
About Threadripper, that was side project for some AMD engineers. They actually put lot of spare time into that. That also explains why there was simply no time and effort to create new socket so Threadripper uses same socket Epyc does. Yes, there are a lot extra pins but simply there was no resources to create new socket so...