Free-market capitalism doesn't cause long-lasting monopolies -- government does
Contrary to popular belief, although a lot of people claim that the competing winners of the free market will, over time, be able to monopolise more and more of the market sectors and that, without government intervening, those monopolies will only worsen and exacerbate inequality, in actuality, it is quite difficult for monopolies to survive for long on their own before their base of power is eroded naturally. Yes, in modern America, there are corporate monopolies that exist, but they've only managed to hold onto power for so long because of government protectionism and privileges, not because of the nature of the free market alone.
Even if an enterprise managed to kill the competition in an entire sector and monopolise the entire industry, it wouldn't last long since without competition, there is no innovation, nor is there an incentive to sell high-quality goods and services, let alone for lower prices since why wouldn't a monopolistic enterprise higher prices to increase profits if consumers don't have an alternative business to flock to? In the long run, profits will decline because of high prices because consumers will turn to buying and using entirely different and cheaper alternatives, alternatives manufactured by smaller businesses that will now see a chance to massively profiteer. Thus the competition will start back up, and it won't be long before other small businesses start selling similar products but at cheaper prices, with higher quality and with more innovation, resulting in the decimation of the initial enterprise's monopoly thanks to free competition.
Monopolies can also spawn when businesses create new products, but opportunistic competitors will quickly compete and prevent any single business from becoming too powerful. Even corporate cartels aren't immune to the inexorability of competition because if a collection of powerful entities unanimously decides to raise prices to increase profits, then new entrants will compete with more innovative goods with cheaper prices. Alternatively, the cartel could fall apart if even one of them starts innovating and selling at lower prices which would destabilise their monopoly.
However, monopolies can be formed and maintained if the government intervenes in the free market with the intent of bolstering the prestige and might of domestic industry for national interests. Government does that through protectionist policies like limited free trade, tariffs, protecting favoured businesses from competition and massive privileges for the elite who collaborate with state interests. Now, these kinds of monopolies aren't necessarily bad if national interests ultimately benefit the world, but the fact remains that free-market capitalism is not to blame for the modern monopolies that we see today, especially in America -- government is the mastermind.
The solution to this problem that doesn't involve a surge of incredible anti-trust policies is for government to free the market even more by severing ties with all favoured businesses and leaving it up to the whims of capitalist nature. Those monopolies could stay in place for years, but they will eventually be eroded away thanks to free competition. Hence, less government means less corruption and a freer economy.