I don't see how including the driver inside the compiled kernel image can NOT make the resulting linux OS bigger than not including the compiled driver.
External modules (on the fs) wont, but we're talking about the bundled ones, right?
I'm old enough to have played the embedded engineer using floppyfw on a spare 486 board screwed on a piece of wood along with a 1.44 fdd and a power supply cannibalized from somewhere. That was my embedded development system nearly 20 years back:)
A bit later I ditched the floppy in favor of a spanking new 4 or 8 MB (megs, not gigs) flash parallel ATA "diskonmodule".
Just checked, I'm surprised that the floppyfw page is still there.
https://www.zelow.no/floppyfw/
Speaking of small distros, I gave a try at both DietPI and TinyCoreLinux on virtual machines and was amazed at how good they perform.
Bundled doesn't mean statically linked, it would be plain dumb if not impossible to add every driver out there into the kernel image; nowadays about everything is dynamically loaded so it doesn't impact the kernel size and doesn't waste memory or CPU cycles unless loaded, which happens only when necessary (eg when a USB device is inserted).
External modules (on the fs) wont, but we're talking about the bundled ones, right?