Governments need a substantial amount of money to operate, and they will get that money through taxation. Whether it is income tax, VAT, land tax, usage tax, or a combination of all of the above depends upon how those taxes affect the nation's economy, and to a degree, the prevailing political philosophy of the rulers.
The US already has land taxes, under the general category of 'property taxes', usually levied by local governments to fund schools and social services. The more you own, the more you pay.
If the US economy were fueled with only land taxes, those taxes would be quite high. Whoops, you just drove all of your farms out of business, and you can't feed your people. You're now at the complete mercy of whatever countries you buy food from. If they start putting the screws to you with high prices, you end up with hungry people... who do desperate things like vote you out of office.
Taxes are not something to be just tossed around. They can have dramatic effects upon your country's economy.
Also... 'tax breaks' are almost always put in place to encourage certain behaviors, not as some subterfuge to pay off rich campaign donors.
Most countries support their local agriculture with subsidies for the very scenario outlined above: food is one of the most strategic of resources, without which your country is in deep trouble. The more you create internally, the less vulnerable you are to a cutoff.
Manufacturing companies get tax breaks to encourage them to provide jobs in your country, instead of some nation that has much lower labor costs. The low cost of shipping internationally has made that situation far more prevalent than it once was.
In the US, capital gains taxes, as in money made on investments rather than working a job, tend to be low. Why not tax capital gains a lot higher? It kills investment. This was seen in the US in the late 1970's, when then president Jimmy Carter raised capital gains taxes sharply, and the drop in investment activity that followed drove the US economy into a deep recession.
Something to keep in mind as some politicians talk about jacking up capital gains taxes to pay for their new and expensive programs... if the economy tanks like it did in the late 1970's, overall tax revenue will be a lot lower. Not only did you not raise tax revenue, you killed a lot of jobs, too, and you're in a downward spiral as your lower tax revenue now has to pay for the increased social services to those people who lost their jobs.
Taxes are not free money, as much as some inexperienced politicians think otherwise. One has to be careful how taxes are applied, as they can have lots of unintended consequences, which are almost always negative consequences.