Yeah when people use “blockchain” as an abstract noun, they actually mean “blockchain technology”. This is precisely the entire point of the post but it’s important to realize that it is improper grammar to just use “blockchain” alone as a stand in for “blockchain technology”.
It may sound ok or acceptable to you now but that’s just because the field is so young.
Some people do say “I work in Internet” but it does sound awkward.
Likewise, it is grammatically incorrect to say “I work in rocket”.
As another example, when Donald Trump says “cyber is becoming so big today” he really means to use the term “cybersecurity” or “cyberspace”. Likewise when he says “nuclear is the single greatest threat” he really means to use the terms “nuclear weapons” or “nuclear technology”.
And yes, “blockchain” works well as a noun adjunct, as in “blockchain storage” and “blockchain database”.