America isn't actually a democracy. The views of the average person have no influence on what the state actually does. The senate is anti-democratic by design (see James Madison: “[The Senate] ought to be so constituted as to protect the minority of the opulent against the majority.”), and all of the founding documents were created by a bunch of slave-owning rich assholes to be as favorable as possible to themselves (reminder that slavery is still legal under the 13th amendment). The elected "representatives" do not accurately represent their constituents; compare the median wealth of a US congressperson (over $1 million) vs the median wealth of a US ~~citizen~~ family (~$121k).

The people who actually hold power in America (and indeed all capitalist nations) are the ultra-wealthy capitalist class, which is to say those who own the means of production (the factories, tools, raw resources, etc that a business needs to produce a product or service). In "bad countries" (Russia etc), they would be called oligarchs. Since its founding, the US state's primary purpose has been to perpetuate and grow the wealth of this capitalist class above all else. The interests of this capitalist class run counter to the interests of the working class, the common citizen. The capitalist wants their employees to work for as long as possible for as low a wage as possible, while the working class wants to work for as short a period as possible for as high a wage as possible. With this in mind, let's now go through policies you listed.

Changing the second amendment. The capitalists generally aren't effected by this, as they live in a safe and secure world separate from the general populace. However, this (and many other things, such as abortion rights and LGBT+ rights) serve as ways to divide the common people against each other, distracting them from the fact that their true enemies are the capitalist class. Between them, the state and the capitalists control almost all of the media in the country, so they are able to push the issues to the forefront. To be clear: I am not minimizing these policies. Things like gun rights reform, abortion rights, and LGBT+ rights are incredibly important; they just don't matter to the capitalists.

The college tuition scam. This one is simple: the financial capitalists make loads of money by giving out predatory loans. They want that money, so the policy will continue.

Free healthcare. As above, the capitalists are making money hand over fist, and do not want to stop. Consider also that "Obamacare" and other policies primarily ease the burden on the common citizen NOT by regulating the healthcare sector to charge lower prices, but rather by simply handing tax-payer funds to the capitalists directly through subsidies.

In general, when looking at the policies pursued by a capitalist state, one should always ask "how does this benefit the capitalists?" America's foreign policy, for instance, largely revolves around keeping the "developing nations" of the world poor and their markets open to "free trade" such that their wealth can be extracted by American (and allied) capitalists at a lower price. Similarly, the US refuses to address climate change because the fossil fuel capitalists would stand to lose money.

The only way to achieve a better future is through the abolition of the capitalist class, which can itself only be achieved through a revolution.

Because that's not the government works. The populace doesn't choose who the candidates are, introduce legislation, or (with relatively rare exceptions) vote on it directly.