My mom claims her cooking is better than the restaurants (arguable) but she's not operating under the constraints of cooking at the variety, consistency and speed that my local diner does. The diner needs to be able to provide hundreds of dishes on short order including on days when the main chef is out. So maybe my mom's once-in-a-while pot of chilly is great but she couldn't run scale to run a profitable diner.
Similarly, sounds like you are hand crafting awesome websites on your own whim and schedule. That's awesome - me too - and I've done amazing handcrafted HTML/js/css for fun.
And then I go to work and manage an organization whose front-end experiences are decidedly not hand crafted and I feel great about that. Our product helps people navigate one of the most important decisions of their life and and sacrificing our ability to iterate quickly at the expense of hand crafted front-end code would be the wrong call. Like my mom's chilly it wouldn't scale.
You'd look at my work product and say "ugh what a badly crafted website" and I'll take the criticism but I wouldn't change it.
If I stumble into the diner at 3am drink and want a bowl of chilly, guarantee positive outcome. At my mom's, not so.
Your question about handling traffic is orthogonal to the topic of design. The answer is that any of my sites would do better, given the same server architecture, because I deliberately limit the amount that needs to be transferred for any particular page.