I guess for simple objects, 3D printing is already sufficiently useful.

I'd still like it to be much cheaper and simpler though. My own tinker days are over; I kind of want to depend on what is cheap and reliable; or at the least very reliable. I honestly can not warrant time investment when things don't work or break down in yet-another-component of my already way too many components heavy living conditions here. 3D printing should be so simple that one never has to think about it. Or print a surrogate 3D printer, to have as a backup device. But what about the materials? I guess plastics dominate.

"It just works" has become true for the top brands of consumer 3d printers in general. They are not simple devices (and neither is a 2D printer), but I don't think they are more complex than they need to be. It's just that they have been iterated enough that they are now mature. But a 3d printer that can print a complete backup of itself is not going to happen in our lifetimes. They are the price they are because of high volumes, off-the-shelf components, injection moulded parts, etc. You cannot make a good 3d printer yourself for anywhere close to low cost of buying a complete one, even if you 3d print as many parts as possible yourself.

Just in the last year or so you can get a $600 printer with a heated print chamber and heated material box that keeps the material from absorbing moisture. This takes them to an extra level of "just working".

There's a small learning curve, and things like lifted prints occasionally happen, but in this post that is literally one sentence describing the problem and another sentence describing the solution. There's good community support.

Plastics not only dominate, metallic 3d printing is not close to being ready for home consumer use, it's $50k for an entry level machine and it still arguably requires a basic machine shop for finishing to be very useful.

But there is still a wall many people hit with 3d printing. When it comes time to design something and not merely print an available file, it's hard to know where to start if you don't already have hands-on experience using CAD or at least an introduction to carpentry or something similar. But this is true of most tools, be it woodworking tools, or visual studio. It takes experience to go from an idea in your head to a series of parts that will assemble together. There will be times, especially in the early days of tweaking dimensions and reprinting things.

In summary, if you want to design things yourself and count this as tinkering that you don't want to do, it's probably not going to be an enjoyable hobby. If you just want to print things like curtain rings and brackets to hold your screwdrivers on an ikea pegboard, it's virtually tinker-free these days.

Huh? 3D printers haven been cheap and reliable for a while now. You can get an Bambulab A1 mini for $200 USD and it’s a work horse. If things break, get a new part online from them and it’s usually plug and play. I’m north of a thousand hours on my P1S and it’s still going strong.