I'm all for a new competitive league, but it won't be easy because a couple of organisations own a lot of the top races. But if there's enough money you can always create new races... What does TDF mean if Majka would win it, or Liege won by Van Gils. When other races in a different competition are won by the big 6.
They just need enough money to start those races, and proper media attention, then eventually RCS/ASO will fold and join the new league. I can imagine Flanders Classics being part of the new league from the beginning, because they are not afraid of challenging the status quo.
That was what was thought when CART and IRL split in the 90s. CART had all the drivers, the best teams, the best circuits. Surely with all of that, with IRL making do with fewer cars, smaller teams, lower budgets and less star power, it would be a decisive win for CART, right?
But IRL had the Indy 500. And although the Indy 500 had a few years of less talented drivers and weaker teams contesting it, the fact remained that there was a large contingent of the audience that
only watched the Indy 500, and CART/Champ Car could never counter that. In the end, within 5 years, CART teams were racing the full CART season but entering IRL as wildcards to enter the Indy 500, and within ten years CART was bankrupt and IRL won the war, but the sport was forever worse because of it, having diluted its own product and resulted in fans defecting, largely to NASCAR, or just walking away. CART tried to create its alternative, the US500, but it was a catastrophic failure.
Do not underestimate the power of the Tour de France; its position as the only bike race many casuals have heard of, or think matters, means that trying to sell to sponsors that they will get major airtime in some kind of Major League Cycling or the Global Cycling Premiership is good and all, but trying to sell to sponsors that they will get major airtime in the Tour de France is better, because even old man advertising executives who know nothing about the sport of cycling know what the Tour de France is.
And the other thing is that a breakaway league would face obstruction at every turn if it didn't have ASO and co on board. ASO would probably protect their trademarks, just like how the Grande Boucle Féminine wasn't allowed to be called a Tour when ASO weren't inviting it, or how the Route de France wasn't allowed to have a yellow leader's jersey. Organising a replacement Tour de France would probably be a problem; ASO would strong-arm stage hosts or threaten to blacklist them if they host the renegade race.
Things like the Champions' League and the Premiership had the benefit that just having the teams on board meant they got the whole product. That's not possible with cycling because you don't just need the teams and riders, you need the organisers because the teams and riders do not own the race locations or the events' histories. It's not even like F1 or MotoGP where the races have the same format, you can just move them around to different circuits; races come in different shapes and sizes built around the geography that they are based upon. Grand Tours and Classics have the format they do because of the countries that host them, you can't just set up a three week race in, say, Saudi Arabia and call it a Grand Tour. Attempts so far to shake up the racing formats (usually in recent years with the sole intention of making sure Jonathan Vaughters stays relevant), like the Hammer Series, have struggled to hit upon a formula that works enough to be worth replicating; that's not to say that an idea that works isn't out there, but nothing has stuck yet.
Any kind of breakaway league without the support or at least the tacit agreement to exist of the major organisers will be doomed to becoming a minor races competition; but then if they have to build the season around the existing Classics and GTs, then I'm not sure it's different enough to what we have now that it would be worth the work that it would take to develop until years down the line, and there's always the risk that it collapses in on itself before ever reaching that point.