It will most likely go away in 2-4 years, when everybody is used to these mechanics.
If someone has an iPhone 8 or SE and upgrades to a whole size display, these people will be lost if Apple removes it already.
To be honest though, unlike a Home button, that bar isn’t self-explanatory at all.
Even my 65-year old dad never needed that visible bar to learn that swiping up from the bottom of the display will get him to the home screen. I had to teach him that gesture once but after that, he was good to go.