zlacker

If your goal is to buy the cheapest machine you can find in the world, chances are good everything you buy is going to come from China. That Prusa Mk3 you bought ages ago can be upgraded to the latest model, which means you have the option of turning that device into a lifetime machine, something ONLY Prusa offers.

Yes, the initial purchase price is higher, the lifetime price might not be.

>>luma+(OP)
Last time I looked, the MK3->MK4 upgrade kit is basically the same price as a complete MK4 kit (very little can be reused. New electronics, motors, extruder)

The upgrade kits are definitely a good thing, going from MK3 to MK3S to MK3.5S was a worthwhile upgrade path and has prolonged the useful life of the printer. But they have their limits.

(And with 3D printing going more mainstream, there's a large segment of the market that has no interest in building printers from kits or stripping down printer to install upgrades - even though some of us find that quite enjoyable)