Yeah, but, Why should you? It's more convenient to have them all in one place, with fast, low-latency access - and if you don't use the Logic libraries you're probably going to have a bunch of third-party samples which will also benefit from being on the fast SSD. Even more so on laptops where you don't want to be continually plugging and unplugging external drives.And, do you really need to install all those sound libraries from Logic, when in the end, you will be using your 3rd party plugins and samples that can be stored somewhere on an external drive? I haven’t used one single stock sound from Logic at all if I am honest.
If you're doing video then, yes, you're probably going to have externals for your video projects, but you'll still have multiple large applications installed which may be creating large temporary files on the system drive.
It's 2024 and a fast 1TB PCIe4 SSD stick costs half of what Apple are asking for an extra 256GB. The way Apple controls their SSDs might be different but there's nothing magical about the flash chips they're using to justify a 4x markup over retail. Not being able to fit everything you use regularly on the internal drive is not a problem that should need working around.