Kind of surprised that these have largely taken over the indie space and it seems it's the 'thing' right now to play.

but they all seem to have conveyor belt mechanics devs insist on nowadays.

I don't know if I could call it a trend

Words, do they mean anything?

A better example that people might be more familiar with would be some of the over the top automation setups people sometimes do in Minecraft. IE with hoppers and pistons iirc.

This is also probably where a lot of people started developing such an interest in conveyor belt type mechanics. Even more-so if you delved into any of the mods like IC2.