It's fine that you like industry better than academia, so do I, but you'd better count your lucky stars that scientists exist.
> At the end of the day, all that matters is: are users using what you built?
How would you measure Isaac Newton's advances in calculus and mechanics or Einstein's general theory of relativity, against say, a web app with a billion users?
The two examples you picked are of incredibly and unusually useful advances in science. I have a friend in grad school who told me he deliberately didn't want to work on anything useful!
If you want to steelman the GP's argument, you should compare the web app with e.g. some niche in pure math. There the trade off between novelty/interest and usefulness to people today is more clear.
I think the two are incomparable and both useful, but it's disingenuous to strawman the GP as saying web apps are more useful than relativity.
As a former student of CS I could pick hundreds of examples of algorithms and data structures, which are now baked into the standard libraries of all programming languages, and therefore in web apps, which were invented in universities. Same with AI - industry is now collecting the fruits, but the groundwork research was absolutely indispensable and very few in industry were doing it until FB or Google set up their research institutes (and we could have another debate on whether those are academic, industrial or somewhere in-between).
Yes, I picked those two examples for the effect or as a reduction to the absurd (not a strawman), because going only by the immediate or tangible value of what one "builds" (science isn't even built, but rather discovered) is not a good way to dismiss academia.
> At the end of the day, all that matters is: are users using what you built?
How would you measure Isaac Newton's advances in calculus and mechanics or Einstein's general theory of relativity, against say, a web app with a billion users?