I'm sure that what you typed here is non-sequitur. Taxation is not government profit. If you have the ability to print unlimited IOUs for other people to exchange for goods and services, and you recapture a portion of what you distributed through taxation every time a transaction occurs, did you "profit"? No. You shrunk supply to raise the value of your IOUs. Taxation of domestically derived income is almost entirely a money supply mechanism. The government doesn't need to create more salaries to do this. They could simply encourage higher salaries (like tightening immigration), and if that wasn't enough they could raise taxes. They have other mechanisms of shrinking supply, as well. While tax money is also redistributed back to various government functions, governments commonly print non-tax money to fund their functions.

Labor pool immigration, in the context of an abundant labor pool, is what it has always been: weakening of labor bargaining, undercutting of market salary, and a separate slew of political motivations.

100m by 2050 reads like incoming feudalism. Best of luck with it.