Well, if that wasn't the worst slippery slope argument I've seen in a while.
That's like me saying "dogs and cats are both mammal pets" and you jump in and say "WELL JELLYFISH IS AN ANIMAL WITH DNA TOO SO OBVIOUSLY PEOPLE CAN'T DISTINGUISH BETWEEN JELLYFISH AND DOGS/CATS". Uhhh, no, that's a massive jump to an extreme conclusion. There's a BIG difference between someone typing "facebook" into a URL bar, and them putting their trash in their mailbox.
I'm not saying you should put literally everything including "change settings" or "access your bookmarks" in the omnibar, merely that combining the URL bar and the Search bar was clearly a common sense UI idea, and even Firefox bowed in after a while.
Your job as a developer isn't to force the user to learn more things. Your job as a developer is not to be arrogant and insist that the user must understand some technical model they don't care about. If they want to go to BankOfAmerica.com, and they typed in "BOA", your job is to make it easier for them to do their banking, even if they're massive idiots when it comes to tech. Human brains have a universal structure, which merely means you need to target the lowest common denominator when it comes to design.
As an aside, this is why Apple products historically are known for being very easy to use by the elderly. I certainly am grateful for the fact that my grandparents were able to learn to use Facetime and looked forward to using that software before they passed away. I'm not sure if Apple's ease-of-use is still true, for what it's worth- they've added a lot of complexity in recent years.
---
Addendum:
This is HN, full of very smart tech people who also happen to be terrible at empathy, so I'll give the usual spiel on empathy (which is usually disregarded by people with overly large egos): The person who typed "BOA" into the URL bar might be a tech idiot, but that tech idiot may just be a really good neurosurgeon, and that person may just prefer to spend their brain cells dealing with their own specialty. Humans are good at specialization, and I'd rather my brain surgeon not know or care or spend too much of their energy in understanding DNS, or the difference in how Chrome distinguishes URLs from search queries. For that matter, I'd rather not have to teach my grandparents the difference between a URL and a search query, either.
If you (the reader) is anything like the average tech guy, there's a good chance you're physically unhealthy in multiple ways, and in an alternate universe there's an internet forum of doctors lacking empathy who are shaking their heads and saying "why can't our patients simply spent a bit of their brain cells and time on eating correct amounts of the precise macronutrients, identifying each of the 13 major muscle groups and stretch and exercise them every day, actually doing the correct amount of cardio where they track if they hit 160bpm and sustain that amount (under age 45), sleep at the precise time each day for optional functioning of the central nervous system, etc". There's probably a mechanic forum that's complaining about tech guys who own cars and saying "why can't they just do a blackstone oil test to know what's the optimal amount of mileage for their car to do an oil change, why don't they routinely fill up their tires to the labeled air pressure to maximise fuel economy, etc". None of what these doctors or mechanics are suggesting something /unreasonable/ per se... but most of that stuff just aren't priorities for an average person to learn and deal with. In conclusion, you can be extremely smart in the tech industry (or any other field) and still be an absolute idiot in so many ways, and that's okay- but you need to keep in mind that the same thing applies to your users for their fields of non-specialty.
In summary: https://xkcd.com/2501/
Full disclosure, I started writing this after I took my sleeping pills for the night, so ignore any grammatical issues or bad structure