I'd say it's more of a "without a way for end-users to compare" --- the average user has no idea how much computing resources are necessary, so if they see their email client taking 15 seconds to load an email and using several GB of RAM, they won't know any better; unless they have also used a different client that would do it instantly and use only a few MB of RAM.
Users complain all the time when apps are slow, and I think that's the best point of comparison.
If I decide that I don't want to use Slack because it drains my battery, then I can't take part in Slack conversations.
Because Slack is the go-to chat application for so many teams, excluding myself from those conversations is not feasible.
End result: I carry on using Slack.
edit: it was 2.0, I misremembered.
This weekend I noticed that Amazon Fresh now delivers the same day—-for the past few months they had no slots. I switched to Amazon away from Instacart at once. The Amazon website lacks some bells and whistles compared to Instacart but it is completely speedy. If Instacart website were satisfactory I would never have switched.
Slow, bloated websites can absolutely cost companies money.
Though the only measurement I think people would actually care about is battery impact, and even that is pretty much hidden away on phones except to the few people who actually look.
But the other problem is: who cares if Discord or a browser's HN tab aren't optimally efficient? You're just going to suck it up and use it. With this in mind, a lot of the native app discussion is technical superiority circlejerk.