First of all, we did sort of have that kind of hockey landscape in the late 90s when the UHL, WPHL, CHL, and WCHL were all filling that hole. The AHL and IHL were developing talent for the NHL and the ECHL had as many teams as it does now or more, and most of them were affiliated, making in the lower league players with a chance at the show wanted to play in.
Back then, there were a lot of multi-millionaires minted by the roaring Clinton economy willing to invest in a hockey team because, well, why not? They brought UHL/CHL/WPHL/WCHL hockey to a lot of places that had little or no experience with it and brought it back in a lot of places that hadn't had pro hockey in a while.
A lot of the players in those leagues were either hanging on to the dream or weren't ever going to be good enough to play in the higher leagues, but riding the buses for a few years beat getting a real job, especially when you're getting all kinds of freebies - beer, meals, housing, and plenty of girls throwing themselves at you because hockey was there and hockey was hot.
It was a unique time in hockey history that was a lot of fun to be a part of.
I think there's room for that kind of hockey talent-wise, but I don't think there is economically. If the average ECHL player is making $600/week, and the average SPHL guy is making $400/week, even with housing covered, I'm not sure there are that many players coming out of college or Major Junior that are going to give up making real money for a couple years to go have fun for $400/week.
On top of that, at a time where consumer prices are rising, fans have less disposable income, which will make it harder to sell tickets. Consider how difficult the entertainment market is in general. Hardly anyone goes to movies in theatres, and not just because of Covid. Most movies and TV shows are available at the touch of a button and 60" HD televisions cost $500. It's hard to compete with that.
Then throw in the arena equation - if you have to draw 4,000 just to break even, which is probably in the ballpark for most midsized arenas, that's a lot. Now make it a product that's not affiliated with and not subsidized by the NHL, and where no player is going to the highest level, and fairly often, not many are even going to the next level - not sure fans are going to want to see that. With baseball, even the short-season Class-A teams had guys who went on to be big stars in the Majors. No one has gone from the SPHL to being a star in the NHL. You could almost say the same for the ECHL. Sure, there are more arenas than there are teams, but there's a reason for that - the arena operator knows it's more profitable to not have hockey than to have hockey.
I'd love to see 30 more successful, well-run minor pro teams, I just don't see it happening anytime soon.