there's no "potential PC gamers" in that statement. The "complicated" parts of PC gaming are the juicy bits. Modding games, upgrading hardware, customizing setups, older games and emulation, all of that requires some base level knowledge of computers and tolerance of their quirks. That's where the best stuff lies and while the Steam Machine will be able to do some of that it's not going to be the same extent a home built PC you have assembled and maintain will, not to mention it's going to be a lot harder on a controller (trust me, i've done some of this stuff on the steam deck, it can be uncomfortable)
If you don't think the juice (mods, new servers for old games, easy, customizable, and accurate emulation) is worth the squeeze (copy and pasting folders into files, changing text files, downloading/dumping BIOS and roms) you weren't going to be a PC gamer in the first place. Consolizing the experience to get players who are already satisfied with their current systems to come over ain't gonna do much.