I play a wargame (Battletech) where the rulebook says "use a bottlecap if you want to as long as you can tell which way it's facing" and even there 3D printed minis are uncommon. For Battletech there's two official sources of minis, plastic from CGL and metal from IWM[0]. IWM has a model for almost every unit published in the last 40 years, but some of them are... very hard to look at. CGL's plastic ones look much and cover the most common units so you can usually get by with just them (although, I did just order a couple minis for an upcoming tournament). If I ever see a printed mini, it's either a) one of the ones where the IWM model looks terrible, or b) a model ripped from the Mechwarrior video games that the person thinks looks better aesthetically.
Where 3D printing has been revolutionary for Battletech though has been terrain. Battletech's played on a hex grid, and ever hex has an elevation printed on it to form hills, buildings, and rivers. There's one company (Thunderhead Studios) that makes STLs of the elevation of the official maps that's very popular. Popular enough that they've actually started mass manufacturing them and selling prepainted terrain retail. That shows up in every event I've been to, even official events where 3D minis are banned. But it's a decidedly ancillary part of the experience for Battletech.
Where 3D printing has been revolutionary for Battletech though has been terrain. Battletech's played on a hex grid, and ever hex has an elevation printed on it to form hills, buildings, and rivers. There's one company (Thunderhead Studios) that makes STLs of the elevation of the official maps that's very popular. Popular enough that they've actually started mass manufacturing them and selling prepainted terrain retail. That shows up in every event I've been to, even official events where 3D minis are banned. But it's a decidedly ancillary part of the experience for Battletech.
[0] Catalyst Game Labs and Iron Wind Metals