It means investors have reasons to doubt about reliability of projects that run their sites on domain names with .io, .info, etc. I am not a technical guy, so I am not sure, but what did you imply that price of a .com site? Millions (really)?
Really
You don't need to be technical guy to look at prices:
Here are the 25 most expensive domain names publicly reported.
CarInsurance.com $49.7 million
Insurance.com $35.6 million
VacationRentals.com $35 million
PrivateJet.com $30.18 million
Voice.com $30 million
Internet.com $18 million
360.com $17 million
Insure.com $16 million
Fund.com £9.99 million
Sex.com $14 million*
https://www.godaddy.com/garage/the-top-20-most-expensive-domain-names/Why didn't those people just bought a cheaper carinsurance.io domain, or a 360.io? Because nobody care about .io domains.
I think .com sites for unknown domain names, have cheap price. Blockchain.com is expensive because nowadays blockchain is one of hottest keywords, and crypto, blockchain are future of human civilization.
For other names, ie. Botcoin.com (if I want to run a new project, with a crypto currency, namely Botcoin), I don't think that domain name is expensive.
Obviously. However a .io domain will be even cheaper. And a .com domian may not even available.