I don't think 2024 is out of the question considering PVL's history of bullishness and forcing and rushing things. It's probably unlikely, but not outside of the realms of possibility.
The NRL 'toppling' the All Blacks isn't out of the question either. In the early 00s when RU was flying many people at the club I helped out at laughed at me when I said that the AFL and NRL would suck the life out of the ARU within a couple of decades unless they made big changes in the grassroots, and look at RU now...
Considering the NZRU's current financial position, the internal competition they face from other competitions for talent, the fact that there've never really had to deal with an aggressive competitor on home soil before, and the All Blacks current position and the sport's reliance on their success to push interest within NZ, I think that RU in NZ is in a more precarious position now than it's been in a long, long, time.
Does that mean that the NRL will 'topple' the All Blacks; probably not in the foreseeable future, but A. it's not outside the realms of possibility, especially if the NZRU make a few critical mistakes, and B. they don't have to. All the NRL have to do to have a large impact is make themselves a strong competitor in the NZ market and take a significant portion of market share from RU in the process.
Rugby in New Zealand is in bigger trouble than they're letting on.
The loss of South Africa from Super Rugby was huge - the South African games timeslots plugged right into the European (Read: UK/France) TV market.. and now with that revenue stream kneecapped it's just down to NZ (great talent, great public interest, but limited money, timezone that coincides with no-one else), Australia (limited talent, limited public interest, slightly better timezone), and the Pacific Islands which bring talent but little commercially.
Super Rugby can't "fall back" on a big Australian market (and big revenue from Australia), because most of the time Australians don't really care that much for union.
Also, just looking at the "Super Rugby Pacific" competition for next year, there's very little potential for further growth in Australia/NZ/Pacific Islands... Perth is already there, NZ is well covered, the Pacific has 2 teams... nothing else can be added without cannibalizing existing teams bases.
Unless Asia and/or America can be brought up to speed & integrated into top tier Pacific competitions (Super Rugby, Rugby Championship), then the revenue growth is limited.
Bringing the argument back to NRL, the potential for growth within NZ & Australia is HUGE. Australia has decent revenue currently - gees imagine where we'd be if we had a NZ derby (even a 3rd NZ club, long term), and Perth.