Why would developers think, in any universe, that paralyzing a laptop touch pad, without a way to undo the fault, would be useful or helpful?
The problem is the other way arround. Your hardware needs drivers, which tells the system what it can do with it and how. But most hardware manufacturer only provide drivers for Windows. Hopefully there are some hardcore people in the linux community that can reverse engineer these drivers and make a version for linux, but since they don't have the full specifications of the hardware things can get complicated and sometimes the drivers wont work.
Also, some drivers contain non-free code, or rely on non-free firmware, because provided by the manufacturer, so they are not embeded by default.
Not all configuration choices could be performed with the keyboard
I don't know about other distos but debian comes with a "text install" option that let you do everything with keyboard.
Are you sure there are some steps you can't perform with keyboard ? You can use tab to focus elements, space to select an item in a list, entre to validate, escape to cancel, arrows to navigate...
How would I add a new driver to linux without being able to boot it at all?
Linux installers are... small linux distros ! You can tweak your installer to provide some drivers during installation time.
You will have to be more specific. Can you give us the model number ? It's probably somewhere on a sticker on the back of the machine.
An older HP 15 had no trouble.
Some hardware is well supported, some other is not. Remember that a lot of things on linux are made by people who have a full time job next to it, and who are not paid to do it.