Yeah, laptops aren't exactly known for having modular graphics cards. And the ones that do severely limit what you can actually use.
True ... but at the same time that's a debatable issue.
Notebooks that come with MXM slots for example can swap gpu's that fit into the slot spec-wise.
Of course that also depends on what type of MXM slot you have in the notebook.
MXM II slots are primarily used these days for mid-range cards.
MXM III slots for high end gpu's.
But I digress ... not always is gpu swapping in notebooks as simple.
Plus the high costs of mobile gpu's available can be a limiting factor, since most manufacturers don't sell mobile gpu's separately but as part of the laptop for the most part.
One important thing to keep in mind for the OP is that Integrated graphic cards cannot be swapped out for dedicated gpu's in laptops, due to the fact they are soldered to the motherboard which of course in turn also physically lacks a connector to which you could connect a dedicated gpu.
Although ... there are laptops with hybrid graphics out there which include both an IGP and a dedicated gpu.
I don't know the market in US, but here in UK I haven't really seen them in high quantities, plus it can be a bit useless at times since dedicated gpu's have a tendency to downclock automatically when not in use. Then again, it could be usable for low maintenance tasks that don't require a dedicated gpu.
Finally ... where did the OP run off to anyway?