Why is there a lack of 3D-printed airgun (PCP/CO2) projects compared to firearms?

We've all seen the massive explosion in 3D-printed firearm development recently. Designs like the FGC-9 and Urutau are incredible feats of engineering. But this got me thinking: why don't we see the same level of innovation and high-quality projects for 3D-printed airguns?

Logically, it seems like airguns would be a much easier and more accessible path. Components like constant pressure valves, regulators, CO2 cartridges, and HPA (High-Pressure Air) tanks face far less regulation globally compared to live ammunition, primers, and barrels.

Given the current capabilities of 3D printing, shouldn't designing and building reliable CO2 or PCP platforms be easier? Is the core issue engineering-related (e.g., containing sustained high pressure in printed plastics vs. the momentary peak pressure of a 9mm cartridge)?