I think the OP may need to put a little less "conspiracy sugar" in his morning coffee.
The "big institutions" can create all the blockchains they want with all the taxes and government oversight they want... and the various governments of the world can do the same... and everyone can feel free to ignore them and continue using Bitcoin (or whatever new and improved cryptocurrency that comes along) that remains decentralised and without the taxes etc.
The Bank of England studied the advantages of it issuing its own Bitcoin-like digital currency. It found using the currency could increase the United Kingdom GDP by $80 billion because it would reduce interest rates and financial transaction charges.
The study doesn't mention tax, but a Bank of England coin would probably make it easier to collect it. On the other hand it's not likely a Bank of England coin could destroy Bitcoin, so Bitcoin users would be unaffected.
https://cointelegraph.com/news/digital-currencies-like-bitcoin-could-increase-uk-gdp-by-80-billionThe less-than 2-minute informative clip highlights key findings attributed to the Bank of England and the IMPACT Institute for the Digital Economy as sources as to what the UK would benefit by issuing a digital currency.
The Bank of England modelled an economy with a digital currency equal to 30% of GDP with a simulated digital currency that was subjected to real world business cycles.
The results suggest a 3% annual increase to GDP. An increase of $80 billion to the United Kingdom GDP, it shows, adding that an explanation was that the central banks digital currency reduced both interest rates and the cost of financial transactions.
The study found that digital currencies will give governments another tool to control inflation and interest rates. Payment and record keeping in digital currencies would be decentralized.
All these would be possible with the blockchain technology that powers digital currencies like Bitcoin.