If you are minimizing the amount of money you spend while doing remote work, you may well be on the "wrong" side of this balance, from a revenue point of view.
It's reasonable to expect you can find individual tourists who use more in infrastructure than they contribute to the local economy - the system doesn't break down so long as the average case means overall it is significantly net positive.
If "digital nomads" are net negative, then I expect you'll see eventually constraints arise. Assuming long enough for a) local governments to figure this out and b) that it's a big enough impact to care about. It's also plausible that "digital nomads" remain such a small number of people that nobody is really fussed about the impact, and the legalities of what they are doing remaining fuzzy is only used as a justification to refuse visa/entry to anyone who has proved annoying to the people who issue same.
German speaking countries do tax tourists.
Company A could simply incorporate a subsidiary in another country, then said subsidiary could hire workers to work for company A's whilst residing in company A's country. No work permit required.
What you've seen in response to this type of thing, at least in Thailand, is that it's harder to stay in the country for a long period of time even legitimately.
Visa lengths across land borders are being cut. Back-to-back visas are now limited. X months in X months out rules are being adopted. It's getting very difficult to stay in the country for longer than 6 months.
It's actually not impossible to get a work permit in Thailand but it is expensive (cheaper if you are an American or married to a Thai citizen). Most people just take the risk.
Also many countries have different controls for tourists or visitors and permanent residents.