The uneducated one here is the one who appears unaware that "installing software" was a thing long before app stores. Security is irrelevant to the meaning of the word, so continuing to go on about it only further devalues your point and does nothing to counter the OP's point.

"installing software" sometimes still consists of

  curl | bash

Like I said, I installed software in many ways back in the day. I typed it in; I loaded off cassette tape; I loaded off disk. One common denominator was loading from trusted sources. My Atari cartridges were store-bought and not homebrew. I went to B.Dalton mostly for the software, and got it shrinkwrapped from the publisher.

I had a number of classmates and colleagues who caught viruses and malware from loading and installing cracked software or untrusted programs... or even alleged porn, from shady sources. This is still a good way to get infected.

When I get on a friend's computer, I often have occasion to congratulate them for being uninfected, and it's nearly always because they "practiced good hygiene" in terms of loading only trusted software from trusted sources.

So you're correct, in that really nothing has changed. Back in 1983 you could certainly "sideload" crap from a pirate BBS and then suffer the consequences. And we all had choice words for people like that.