The problem is just that the ones (politicians and companies) writing the laws are the ones who want the loopholes. The lawyers who could work on improving laws, are instead helping companies find creative avoidance techniques.
This unrealistic wishful thinking you seem to be exhibiting is something I think politicians intentionally prey on. If some politician can convince you that it is possible to “fix this”, but without the all the obviously mandatory costs and tradeoffs, then they can also potentially convince you that they can and will do it. This particular policy issue has been a part of many political platforms, yet nobody has ever “fixed it”, because it cannot be fixed (at least not without also ruining a lot of other things).
> This unrealistic wishful thinking
Quite the contrary, for some reason you seem to have a cognitive dissonance about the sheer complexity of tax laws. The loophole is not as simple as “anything can be offshored” - there’s a significant nuance involved in what is possible even now.
This is also the reason most developed economies have given up on regulating transfer pricing any more than they already have, and instead the strategy has shifted to trying to get the tax havens to implement or increase their corporate taxes. That’s why the “global minimum corporate tax rate” idea has recently emerged, and why the EU uses their black and grey lists to coerce foreign jurisdictions to write new tax laws. This strategy is arguably more effective, but still a complete failure, because you have some tax haven jurisdictions that simply ignore the pressure, and other tax havens are simply never sanctioned because they have sufficient leverage in the global economy to avoid the attention entirely.
It is very literally a choice between corporate tax, or globalization. There is no way to have both.
Governments do it just fine for normal individuals. Small to medium businesses also pay their taxes pretty fairly. It says something profound about the system, if the avoidance needs large complicated structures to do so.
Something something lack of moral compass.
Real people also manage to avoid their taxes all the time. People complain about the rich not paying their taxes every day. People can also offshore their income in mostly the same way a company can, with the only additional complication being residency requirements. I just finished watching the F1 qualifying, a sport that has 1 Monegasque athlete, but nearly half of its currently active athlete living in Monaco.
If you want a system of global tax governance, then you’d need a global government. Something we don’t have, will not have, and a lot of people tend to be especially resentful towards any of the efforts to create one (or something that behaves like one).
A solution could be to tax offshore expenses with the difference in tax rates, i.e., min(0, corporate tax rate -destination company's corporate tax rate)%. That would eliminate the advantage of lower tax rates at the destination.
Another way would be to allow deducting only min(100, 100 - corporate tax rate + destination company's corporate tax rate)% of the offshore expenses. That still provides benefits for shuffling profits offshore, but the origin location gets some of it.
Also, aside from the fact that this policy would fail, what you’re describing is a rather extreme import tarrif, which is a highly protectionist policy.