Your automotive analogy is interesting in that it illustrates that you just don't get it. Web design is about BUILDING sites, not using them. The drivers would be the visitors to the site, NOT the person/people creating it. You don't do a whole lot of design/creation/building while driving, do you?
Honestly, I wouldn't want to drive a car designed by someone who doesn't know those fundamental engineering principles you are dismissing out of hand. That's like hiring a matte painter to design a building instead of an architect -- just ask NYC how well that works out... or saying you want to be the next "cake boss" but don't want to learn to bake, frost, work with fondant, or do piping... or saying you want to build custom bikes without learning how to weld, cut or shape metal.
It's not about driving the car, it's about creating a car... that's what that pesky word "DESIGN" means.
Means more than that in fact, since making a website is about a heck of a lot more than what you happen to see on the screen in front of you as a visitor to websites OR as a "designer" -- see why most of the PSD jockeys sleazing out pretty pictures and having the giant set of brass to call themselves "designers" typically aren't qualified to be designing a blasted thing so far as the web is concerned...
... and why WYSIWYGS and off the shelf templates are accessibility and design disasters; for the most part even when they are pretty they are effectively useless to actual visitors to the sites they are used on. The very notion of a WYSIWYG being the antithesis of what web design is, since with the plethora of screen sizes, device capabilities, font rendering engines, default font preferences, and user enabling/disabling of fancier bits out of distrust or crappy service providers, what the 'designer' sees on their display is pretty much guaranteed to NOT be what everyone else gets.
Hence concepts like semi-fluid layout, elastic layout, responsive layout, separation of presentation from content, progressive enhancement, and all the other means of creating easy to use (for the visitor) accessible fast loading gracefully degrading designs.
NONE of which you're going to get from some WYSIWYG or "site builder" garbage; such 'tools' do nothing but delude the ignorant into THINKING they can build a website; which they do -- right up until all the issues with that approach bites them in the backside. NEVER seen a site build from that approach that was worth a flying purple fish -- they are universally incompetent rubbish since they are basically built using a sleazy shortcut.