There is no doubt that the modern NBA has a lot of elite perimeter scorers. Stephen Curry and Kevin Durant operate well from beyond the three-point line, as do other stars like Damian Lillard. This is an all-time era for guard and forward play, but not necessarily for the big man.
Metta World Peace has recently claimed that the game is being made harder for big men while adding that the NBA allows guards to push into bigs, while big men aren't allowed the same level of contact. Joel Embiid has notably commented on the officiating difference between him and guard Trae Young, suggesting that they are not being called the same way.
There is no question that referees sometimes miss calls. However, the playoffs are an intense environment, and sometimes referees let some contact slide that they wouldn't in the regular season. While it is a guard-heavy era currently, perhaps the big man will reign in the future once again.