[Havoc]

They’ve been making merch for years, just perhaps nothing of comparable mechanical complexity

[shapefrog]

tshirts / hoodies != custom designed mechanical item with many moving parts.

[DrudgeCorporate]

Their engineer that they hired specifically for this task had years of previous experience. It's stated in the video.

[yurishimo]

They have in-house clothing designers as well that specifically tailor each garment before mass production. None of their merch from the past 2 years is "off the shelf" in any way.