I love the creative idea. I love to hear new ideas and I encourage everyone to share ideas. So please don’t take my words as criticism. They are indented to help improve the idea as far as my experience allows.
Elastic or rubber bands would introduce flex that could cause you to lose precision. Also they would break down and tear very quickly under pressure. As a test you can see how heat and pressure destroys most elastic bands. Take a band and stretch it out quickly several times. Then feel the heat it generated then notice how it isn’t as tight as it used to be. Elastic chemically breaks down quickly with heat and pressure.
They only way I could see to make that work would be to print nylon caps for the bearings. Nylon can usually take the abuse and it can cause rolling parts to be quite. For instance garage door rollers. The upper end rollers are made out of nylon because they are quite and strong.
The problem with nylon is that it is very difficult to 3D print. Not all machines can handle the high temperatures required. And it shrinks when it cools so it takes calibration trial and error. It requires more skill and experience to print well.
Not impossible but a little difficult for new makers get right.
again I like the idea.
Jeffeb3 is right about the tolerance and offsets. Mixing the different sized parts won’t work because they won’t line up. So if this idea was adopted it would have to be a new universal size design.
Can I just say I love this community. People who love to tinker and come up with new ideas. Thanks everyone! And Merry Christmas!