Hahahha good one, here you go - a pool from 2017 (won't do the research for you to find a recent pool with similar result) with over 21 000 voters:
https://www.androidpolice.com/2017/04/30/weekend-poll-screen-protector-or-no/
tl:dr
51 percent of the voters are not using any kind of a screen protector, 49 percent are using.
Quite a lot more people are not using one as you think and a lot are using it so it's normal to have a market for them. So, you think apple should not consider the 51% of the people that are NOT using a screen protector? Also I can't see anywhere on the box or media that using a screen protector is basically a must, because the phone can't survive alone in a pocket for a week without damage (and as you saw on some of the pictures, the damage can be absurdly big). Nor I can see a preinstalled screen protector and a warning that the screen scratches easily.
Seriously + for what you need that extra shatter resistance glass if you slap a high quality screen protector that will protect your screen and break instead of it? The iphone 11 for you will survive the same way as iphone 6s, 7, X, xs, etc.
This issue is on us, the other 51% of the buyers.