The six guys OP is talking about who are averaging 30+ are Embiid, Doncic, Lillard, Shai, Giannis, and Tatum. All six of those players have incredible, almost unprecdented skill sets for their size. Which one of them wouldn't be able to average 30ppg in previous eras?
Heck, Steph Curry is the greatest shooter in NBA history and he's not averaging 30ppg in this supposedly "easy to score" season. Kyrie Irving has the "greatest bag ever" and yet isn't averaging 30ppg. Donovan Mitchell, Ja Morant, Kawhi Leonard, Lebron James, are all incredible offensive talents yet none of them is at 30ppg.
Just look at the NBA scoring leaders and try to see how far down the list you have to go before you find someone who doesn't have a generational skill set. This era is fukking loaded. Every single one of those players could get buckets in previous eras. Can you say the same about the high scorers of the 80s and 90s?
Kelly Tripucka isn't putting up 26.5ppg in this era as a 6'6" forward posting guys up all day.
Michael Adams ain't averaging 26ppg as a 5'10" guard with no hops and a broke-ass jumper.
Jeff Ruland wouldn't be a 20+ppg offensive force as a barely mobile truck driver with no game outside 6 feet.
Moses Malone ain't gonna have a 31ppg season or 3 MVP years in this era with his limited offensive skill set.
Tom Chambers isn't a 27ppg scorer with no athleticism or 3pt shot.
Kiki Vandeweghe ain't getting anywhere near 30ppg again as a shorter, less accurate Dirk with less range.
Adrian Dantley isn't a 30ppg scorer year after year as a short Carmelo with no 3pt.
And lets not even talk about how a certain shooting guard with a broke jumper and no left ain't gonna be a 27ppg scorer, or a 6'6" forward with the worst 3pt numbers in NBA history isn't gonna put up 28ppg.