I get your point, but ...
Casual WWE fans are not the ones buying NJ tix & subs
Very few casuals have the WWE-Network
Those are mostly wrestling fans mixed in with WWE-diehards
But don't underestimate the HC's
Look at pops Styles got when he debuted in WWE
Similar with Nak, Owens, etc in NXT
NJPW sold-out & could have easily done 10k tix in states if they went to a bigger venue
You have to remember that only 1-1.2m US based subs are monthly for WWE network
The rest of the viewers watch TV because its free or have it in the background
the cores that go to Mania week, go to all those indy shows & know the biggest non-WWE wrestlers like Bucks & Omega
Trust if Omega came out for RR, he would get the pop of the night
The 1m extra TV viewers the next night on RAW might be confused though, but they are not the paying audience anyway