[Boyso]

It's all about tolerances. These clones are cheaper for 2 reasons. Cheaper material, looser tolerances.

Some companies cannot afford tighter tolerances as it means bigger production costs.

Clones uses loose tolerances and next to no quality control. This means that your VSR10 clone may be 3/1000th of an inch off somewhere and it will mean that a high quality part like Laylax (With good tolerances/QA) will not fit. These parts were made with Marui's tolerances in mind. If you don't have the same tolerances, it won't work.

A clone springer will never be as good as a TM one.

And this is especially true for springers! When you can only make one shot, there's next to no time for adjusting for your poor accuracy. With an properly tuned AEG, you can deliver massive volume of fire to compensate for accuracy. You'll just waste precious BBs with a clone springer.