No tool is ever a substitute for discipline.
My experience is exactly the opposite. Humans are too fallible for discipline to ever be reliable. If you want something done, automate it.
The enterprise wants everyone to be a jack of all trades and to understand everything. Part of the reason for the massive layering that takes place is so that things are compartmentalized and easier for an individual to pickup and put down as they're shuffled around from project to project. Standardization, documentation, consistency, and discipline are essential for enterprise developers to be able to quickly grok a project and make the necessary changes.
Automation also plays an important role because it allows less skilled and knowledgeable individuals of lower pay grades monitor the blinky lights and only call on the big boys when things fail.
Do you work in a team? Or do you plan to hand over that code to someone else for maintenance at some point in time? If not, then by all means, go ahead. Another advantage of ORM/web frameworks is that they are properly documented and only have to be learned once. I once had the displeasure of maintaining someone elses custom 'framework' with no documentation.
Did anything of what the parent wrote sounded like it was worse for teams?
At least that's why I would consider working on a team like that much worse.
http://php.net/manual/en/function.setcookie.php
grep -r setcookie in my code will let you find out if i sent any cookies. Incidentally, this is the same grep I would have to do on a framework, but the framework (pick one) is probably bigger than all of my code.
As an example -- we used to have a WordPress blog; now we have a custom blog that's a total of 3628 lines of php that lives on the frontend and I included the Makefile for deployment and some extra include files cause I don't want to spend the time to consider which ones aren't needed. Content is from text files pushed with another process.
By comparison Wordpress includes 298,643 lines of php. Wouldn't you rather dig through all of my code than all of theirs? (Yes, Wordpress has a bunch of features -- but even when you turn them off, the code is there lurking, and sometimes it still runs)
Someone else from my team fixed up the mobile support and handles the css/javascript -- they were able to just look at the code and do what needed to be done. (The mobile page was broken in our install of Wordpress too, so I got it to parity anyway)
It took me about a week to write it and polish it (three days dedicated, including exporting the content from mysql, two days I was doing other things too), but on the plus side, I don't need to spend half a day to figure out how to deploy a Wordpress upgrade every time they have a security release; there have been 12 security releases since then, so I've earned a day of my life back.
They wouldn't know vanilla SQL, HTML, WSGL, etc, --decade old standards-- etc, but they would know some random framework like Flask?
Well, Flask is 95% just two persons [1] and 5% among 10 others. And the one responsible for creating it and writing 60% of it doesn't even have it as his first priority (has multiple other libs, codes Go, etc).
A lot of widely used Javascript libs are not even that lucky. Heck, GTK+ itself, one of the pillars of Gnome and used by millions, was down to 1 maintainer a few years ago, who openly complained about it (not sure if things improved since).
Unless it's some large, focused project with bit traction, tons of books and courses on it, etc., like React, Angular etc (usually with some corporate backing too), a lot of the things that pass for serious frameworks and libraries are anything but, and a lot is hardly a "community" project either.
Some person slapped together something and thousands adopted it because "frameworks are better than writing your own code". Then the person moves on, or some small team that leads the project decides to rewrite it from scratch to try new stuff because they have short attention spans, and you're left with an abandoned code in your hands, which you haven't wrote yourself, and don't have time to understand fully.
A framework can be good to start with if you're doing stuff close to its confines, but otherwise its how Joe Armstrong described OOP: "You wanted a banana but what you got was a gorilla holding the banana and the entire jungle".
Notice how all major companies, from Facebook and Google, to Twitter and Microsoft and Apple etc have written their own frameworks.
Perhaps their programmers didn't know that already existing frameworks are better? Or were they focused on their actual problems and pain points, instead of lowest common denominator solutions?
However, if your application is more complex, you should be careful. Chances are, you will add your own layers. And chances are, they will suck more than some popular framework or ORM. It's not that you make a conscious decision, a plan to do so, usually it's bit by bit. And having seen all the custom frameworks and shitty ORMs (because it seemed easier at some point early in the project), don't write your own ORMs for the sake of the maintainers mental health if not your own.
As a professional cowboy -- I detest layers; if it's running on my server, I need to support it, even if i didn't write it. An ORM or a web framework adds thousands of lines of codes and usually two or three layers of indirection. It's way less effort to just output some HTML, or just make a database query, than to learn a framework or ORM, and as a bonus it's usually faster too. Also, it's a lot easier to fix slow queries when there's one place that has the whole query (with placeholders where possible -- I may be crazy, but I'm not insane).