Mark Cuban would agree with you about investing in companies adopting the technology instead of in crypto. But two blockchains have arrived at a special place: Bitcoin and Ethereum. Both of these now have a history much like gold and silver, investment grade baseball cards, famous art, ebay, etc. All these things have been adopted as a standard and history shows that it is extremely hard to upset that once it takes hold. Ebay sucks yet they get the vast majority of the auction traffic. It is hard to change that and many have tried without success.
If you fight all the correlations of history on this then you have to explain why it is different this time. It's like the people who argue against owning gold and silver. It just does not work the way they think it does. People will always use gold and silver as a store of wealth regardless of why you may think it is idiotic. It just is. Gold isn't going to zero. Neither is bitcoin. This was not the case 10 years ago. Bitcoin is now in a very different place.