There are usually between 5-10 players with 100+ receptions in recent seasons. Here's a list of the players with more catches than Robinson in 2020:
Stefon Diggs, Davante Adams, DeAndre Hopkins, Darren Waller, and Travis Kelce. Have you heard of any of them?
To me, keeping up with players on other teams is a bit different than never having heard of an accomplished former Pro Bowl wide receiver. No big deal.
I'll be rooting for Robinson, too. I can assure you that, if he's healthy, he'll be a very good player for the Steelers.
I'm a bit more excited about a 6'2, 220 lb. NFL veteran with 500+ receptions and 40+ touchdowns (who's still in his 20s, not a worn out has-been) than I am about a guy who spent the entirety of his lone season on the injured list and has yet to play a single down in the NFL.