No owner would agree to such a huge paradigm shift to the status quo. It’s just my pie in the sky, fun idea that I think would actually work. What the owners really care about, and the players, is money. Some would argue this wouldn’t bring in as much money, or the B league teams wouldn’t make as much money, or the B league players. My solution to this is to keep the same salary cap for both leagues, and maybe make the cap penalties in the A league more harsh than the B league, with the penalties paid to the B league teams. Also, keep the salary floor so B league teams still have to pay their players fair salaries that are comparable with A league teams. Also, as an incentive for winning promotion to the A league, each player on the B league team would get a 1 million (or 2 million?) bonus. This is incentive for players to sign with B league teams to win promotion.
The international cup competition would also bring in a bunch of money with the TV deals to Europe.