What you're touting is a magical elixir-like utopian crypto that doesn't appear to exist. From where I'm standing all I can see is an absolute clusterfuck with a million shysters all competing to make a quick buck in the confusion. It's not too dissimilar to the gold rushes of yore except gold had the advantage that if it all went pear-shaped you at least had the gold in your hand.
In order for a truly independent crypto to succeed it requires both stability and widespread adoption. That's not going to happen when you have dozens of new currencies appearing daily and every Tom, Dick and Harry manipulating their relative worth with their crazy investments. It is literal anarchy with a good dose of libertarianism thrown in for good measure. Not really a great recipe for success.
Widespread adoption also means that it has to be accepted by the governments of the largest economies on the planet. which essentially means the USA, The Peoples Republic of China and the European Union have to get on board. The US might be a bit more receptive what with their historical fondness for snake oil but the EU has a lot of it's very existence tied up in the Euro and China would very much prefer something that they can control and manipulate - so they'll no doubt create their own which kinda takes away from the whole independence thing.
Bitcoin literally ticks all the boxes I presented (the anonymity of cash, convenience of near-instant international transactions, is (generally) an appreciating asset, does not require physical security or effort to transport and store (such as gold, silver, or cash), and is decoupled from the financial health of any particular country). That is just one example.
The only uncertainty is whether Bitcoin will be the crypto that ultimately succeeds and retains value for another 5, 10, 50 years etc... Governments may not accept cryptos as a form of payment (yet), but they are recognised as an asset, and are taxable.
I already agreed with your statement that any long standing crypto needs stability and widespread adoption. The only way we will know whether any of the existing cryptos tick those boxes too, is to to wait.
Also I agreed with your argument there are too many cryptos at the moment, and the bulk are scams or won't survive. It is a crowded space at the moment and 1% or less are likely to survive the long run.
But to totally write off the idea of cryptos ,or blockchain technology in general, is short sighted. Even if Bitcoin or others aren't around in 100 years, we are guaranteed there will be others taking their place and be more widely adopted.