This is an interesting point and made me wonder what percentage does bitcoin contribute annually according to the numbers in the linked paper.

Bitcoins annual estimated e-waste: 307 000 metric tons Global annual estimated e-waste: 53 600 000 metric tons

307 000 / 53 600 000 * 100 = 0.57 %

I don't know if the numbers in the linked paper and the following paper can be used together as I haven't read both, but I've taken the global annual e-waste estimate from here as unfortunately the linked paper does not mention it in the abstract: https://www.itu.int/myitu/-/media/Publications/2020-Publicat...

While I do think Bitcoin in its current form is a problem and the developers should start thinking of solutions sooner than later, I think starting with Bitcoin to reduce total e-waste is misguided at best.