Check the network panel. See the Megabytes of html and js a browser needs to work with.
It’s a miracle that browsers can render all that in the seconds it usually takes them, and if Chrome is a second faster, it’s due to the billion $ company behind investing the GPD of a medium-sized country into optimizing it.
As a FF linux user both at home and at work I can't say I've ever noticed FF being consistently slower. Having said that I have used nothing but FF for the last 20odd years so maybe I'm just used to it...
Clothing tends to be cut from patterns of 2D shapes that are then sewn together. In theory if you measure certain key parameters of the customer you can adjust a standard pattern to fit them without further refinement. Imagine if you took a thin man, fat man and normal man then measured them all, and designed a pattern based on the normal man. Then found weighting’s to scale the pattern to the thin man and fat man. You could then (in a naive fashion) interpolate between these weighting’s to create patterns for every man inbetween. That would be your algorithm.
Not too well, no. Off-the-rack basically requires good luck and a good eye for how a suit's supposed to fit to find something that works well enough to still be tailored some (rather than extensively, or simply being hopeless) so it'll look alright.
Even shirts, if the sizing's not two-dimensional (trim, slim, regular, loose, or some similar range of cut types aside from just S/M/L/XL and so on—so Large Slim as a size, rather than just large, for example) you're not even gonna get close to an alright fit, most likely. Good dress shirts provide more detailed measurements, but even there, made-to-measure will give you noticeably better fit than off the rack.
In the sense of getting close to a ballpark that can be refined in later fittings it’s basically the job of a tailor. In the sense of being able to commodify it, as I understand it, no.
As well as there being a technological barrier there is also the cultural barrier in that bespoke suits mean something. I actually think the bra thing makes more sense from the POV of offering better comfort.
They were trying to design custom-fit bras automatically, based on 10 measurements of the body. But 10 measurements are too few to capture the wide variety of boobs that exist, and it was too expensive to gather ground truth examples (because you have to pay for expensive custom fit bras for a load of women) so they failed.