You're certainly right in some cases, though I do think its a mix of truths.
Some of them do realize the actual situation and are ladder pulling, but mixed in with that there's also a pervasive offshoot of hyper narcissistic survivorship bias that in my experience a lot of modern tech entrepreneurs suffer from where they really are actually shockingly blind to the build-up of everything that they then built on.
Like the Internet existing for them is taken as just a given like the earth and the seas being here, but "taxi cabs you hail through the internet"... that's the real invention!