I do not agree with one of the points. Regulation by the state can only spoil bitcoin. This will affect the cost. There will be taxes. There may be illegal activity here. But it is everywhere. Both on the Internet and in the real world.
Well in the very unlikely case of strict regulations by all or the majority of countries that is actually the worst threat to bitcoin. If countries make exchanges illegal then you can buy or sell bitcoin (exchange it against fiat) and some countries are even attempting to restrict the online use of bitcoin. That would certainly be the end of bitcoin and cryptocurrencies.