> But the govt increases debt limit each time, what's the point of having a debt limit then?
I'm not an economist either, but just because the government has repeatedly increased the debt limit doesn't mean that it will always do so. Imagine a bank offering an account holder more and more credit as their earning potential and credit rating increases. That doesn't mean they would offer infinite credit.
A good way of putting the US situation into context is to look at the national debt as a percentage of GDP for various countries in the world.[0] As you can see, there is still some way to go before the US reaches the levels of Portugal, Italy, and Greece (three of the derogatorily named PIGS countries[1]) and a huge gap before reaching the levels of Japan (which admittedly has its own problems[2]).
> taxing wealth over income only makes sense if income taxes go down.
Citation needed. The median US household pays the equivalent of about 8% of their net worth in taxes every year, but billionaires pay a much lower rate by that metric. So if a wealth tax was created for wealth over $100 million, it could be set such that billionaires only feel the same relative burden as the average family.
> in few cycles even that budget will be not enough.
Why do you say that? For some historic context, you can look at how the federal budget has varied over time as a percentage of GDP.[3] "During the 39-year period covered here [1971-2010], federal outlays grew somewhat faster – 0.6% per year – than GDP."
[0] https://worldpopulationreview.com/countries/countries-by-nat...
[1] https://en.wikipedia.org/wiki/PIGS_%28economics%29
[2] https://en.wikipedia.org/wiki/Lost_Decades
[3] http://stats.areppim.com/stats/stats_usxoutlaysxgdp.htm