As one of the few NFL & MATI enjoyers, I must say that Stalker Null Child is wrong about a few things, but he's particularly wrong about teams that win just getting more money and paying for better players. (The reason the Chiefs lost was 100% because they traded Sneed though, also the Packers are the best team)
The NFL is one of the better sports leagues when it comes to avoiding this. Every NFL team has a salary cap of 255 million dollars/year that can be used to pay for players on their rosters. Every team uses this amount of money. Other sports don't have this, and it's absolutely a problem that big market teams simply take in more money, and have more money to pay for a loaded roster, and then simply win more. Baseball is especially bad at this, and it's why teams like the Yankees and Dodgers constantly are competitive.
In the case of the NFL- a team's success is mostly chalked up to players, who in turn will demand higher contracts as market compensation for playing their position at a high level. Any team that's successful for too long will soon find that they cannot afford to keep all their players at increased rates due to the salary cap. This is one of the big drivers of trades, and it's a natural balancing mechanism to equalize the talent pool between the teams. The other big balancing mechanism is the draft the worst performing teams get preferential draft picks- drafted players are on rookie contracts (relatively cheap for several years) making the highest draft picks (usually the best players in college football) extremely valuable as you can get extremely talented position players without a huge hit to the salary cap, especially high drafts spots can also be used to trade for current, proven players or a handful of lower-level draft picks depending on your team's needs. The average NFL player's job is extremely physically demanding, so the productive lifespan of most position players is in the single digits, further encouraging teams to draft and develop young new talent who have more years to play left. There's a whole lot more interesting stuff with how you can structure individual contracts to try to essentially put off playing for players down the road (something teams often do if they're competitive now, but need to fill critical gaps in the roster) which can also bite your organization in the ass as you may end up paying for players even after they've gone to another team. There's a whole autistic/interesting meta game that's played every year with roster building that's really interesting. It's far more complex than just "the richest teams can afford to pay more money and keep winning".
The system is set up in a way that makes multiple super bowl dynasties extremely difficult to pull off and thus what the Chiefs have been doing or the Tom Brady Patriots doing so impressive/frustrating for everyone else. It also makes the teams that seem to perennially be losing organizations more remarkable- they often get called poverty franchises, but this is a misnomer, it's more pathetic because they get as much money to play with as everyone else, they just consistently suck at team building often due to terrible ownership that demands immediate turn-arounds and wins at the expense of longer-term, well-rounded roster building.