I do agree that the "Profit-taking" teams in MLB is a problem - the teams that have lower payrolls than they receive during revenue sharing. This does hurt the whole league as it leaves those markets under-served, with little chance at a multi-year run of competitive baseball.
I think that what the Dodgers did this year - backloading a $550 million contract and relying on revenue growth to deal with it - is a potential new threat to competition, as most markets won't be able to do that. I don't know whether that will make a huge difference until we see the results.
I think that baseball has an impressive degree of parity despite these couple of problems. The teams that make the playoffs nearly every year - one of them has a lot of resources (The Dodgers) but they also have a front office that is as good as any in the league and regularly develops their own talent. Other franchises that regularly make the playoffs get there because they have skilled employees. The Rays, the Astros, the Braves, the Guardians - they have front offices that are doing their job. With a few financial exceptions (Pittsburgh, Florida), the teams that are always at the bottom of their division are there because their front offices are poor. The Rockies, the White Sox, the Mariners, the Royals - they can't compete because they can't identify or develop talent, so they make the playoffs once every decade or so.
I think it's especially impressive in baseball that teams like the Yankees and the 2023 Mets cannot buy their way to the playoffs. That tells me the financial difference between teams still is less importance than the skill of the front office. Teams like the Rangers make the playoffs by spending money, but who was key to the Rangers last year - Adolis Garcia in the playoffs, for example, was a guy they picked up and developed. The Diamondbacks made the playoffs last year. The Rays overcame a key player seemingly having his career ended early in their biggest contract. Aside from the teams where the owner is a parasite just taking in money, parity in MLB is mostly fine, hire good people, have them do a good job, and your team will have a competitive run soon enough.
Finally, I see no problem with the cycle of competing and tanking. That is absolutely normal in most sports. Normal behavior in sports should involve a team developing a lot of players, peaking for a couple of years, trying to win a title, then backing off to rebuild, get younger, and restructure their financial situation. The Golden State Warriors drafted and developed an incredible team, but it seems like their guys have gotten old and there's only so far they can push them. The Buffalo Bills couldn't get past Mahomes in their best chances, now they're losing a lot of their players to free agency. The teams that manage to shortcut these cycles tend to be ones that have elite front offices regularly developing players - the Chiefs and 49ers in the NFL, the Rays and Dodgers in MLB.
The NBA, because of the dominance of a few stars and the way their max contracts work, has in many ways been the least competitive, lowest parity league, but even with them we're now seeing teams go through cycles. The Bucks weren't that great, but built a great team and won a title. The Heat are seemingly an elite coaching and front office combination. The Spurs fall apart, get a #1 draft pick, then build championship teams around them. The Thunder sold off Durant, Harden, and Westbrook, piled up tons of draft picks, now those draft picks are growing up and they're back to a #2 seed. This is normal, it's how leagues should work.