Not many countries rely on income taxes. For example, Thailand has about 11% tax revenue from personal income tax: https://www.oecd.org/tax/tax-policy/revenue-statistics-asia-... Mexico is 20%: https://www.oecd.org/tax/tax-policy/revenue-statistics-latin... Vietnam is 8%: https://www.oecd.org/tax/tax-policy/revenue-statistics-asia-...

It is very hard to collect personal income tax in developing countries. OP's tax revenue claim just doesn't match the data. On the other hand, corporate tax and VAT are very easy to collect. Digital nomads are very good for these revenue streams.

It is true these digital nomads don't contribute to social security benefits. But they also rarely take from it. So it is a mixed bag.