Blockchain sure, but why do you think self-driving is a bubble?
Yes, we've all met people who read about Bitcoin and Ethereum in the WSJ and felt incredibly smart when both declined from their highs.
But what about the ICO money raised in 2018? It's likely over 5 billion at this point.
Am I going to look at every MLM scheme or perpetual motion machine to explain in detail why this new one is just as bad as the rest? No. I looked at a bunch, formed a general impression and a reasonable theory as to why they're all bunk, and have stopped wasting my time.
If somebody has a specific one that they'd like to argue is different I'm willing to listen. But I'm not going to look at 500 supposed startups and figure out the flaws one by one.
[1] https://quoteinvestigator.com/2013/12/13/pony-somewhere/
"They ripped off over 5 billion dollars in cash, that means it's not a bubble." Well, doesn't that actually tell you the opposite? That people threw money at obvious scams just because the scams used fancy technology and a buzzword?
If you have proof that one of them is a) a real business, b) is likely to succeed, and c) is using a blockchain in some way where it's both necessary to the business and superior to other ways to store and verify data, then please share it. Otherwise you're the one making hazy, unsupported general statements.
I'll grant Bitcoin has some utility for light crime, like buying drugs or evading capital controls. And it's the technology of choice for ransomware and some kinds of electronic fraud. (It's bad for serious crime as it leaves too much of an audit trail.) But I don't think crime is a very good domain for running real businesses, so that doesn't count for me either.
You then respond by asking me to present proof to you as if your own ignorance is somehow compelling.
As I said, I'm not saying all of them are scams. Indeed, I specifically mentioned two other possible classes they could fall into. And as I think is clear from my initial comment, I'm open to the possibility that someone will find a use for blockchain that enables some sort of viable business that couldn't be done with other tech.
You of course don't owe me any explanations. But you're the one who jumped in with a variety of handwaving contradictions to my comments. So if you want to to be taken seriously, backing you agitation with evidence would be a good step.