Intel did literally say that. Even just logically this should be obvious. Good example is M0 patterning. On Intel 7 that is 40nm (if memory serves) and done with spacer based pitch division. Okay sounds doable with dry DUV (160nm core feature) and with way more etch, dep, polish, and metrology tools to form the same feature. Intel talked about 18A using direct print EUV for fine pitch metal layers at SPIE. There is simply no way to carry over all of that extra dry DUV tools and extra supporting hardware. Also what tooling is "the best" is now different because what you are doing is different. That SAPQ process would presumably have to deal with much greater aspect ratios and very different hard masks and chemistries.
Another good public example is Co metal lines vs Cu metal lines with a Co liner. Intel 4 and GF 7LP papers have both shown that for metal lines that the hybrid approach offers superior performance AND acceptable EM lifetime. Even TSMC and Samsung were using this at their 16/14nm. But because Intel was on their island they did their process the Intel way on the Intel tooling rather than using what the industry conscience said was the most effective process/tooling combo. I have to imagine there are tons of other examples of different process segments where Intel in their isolation from the rest of the industry/vendors was doing something suboptimal from what others eventually figured out.
A final example is that 18A and beyond are GAA and BSPDN processes. Both introduce tons of brand new process modules and obsolete others. An example that immediately comes to mind is W fill of the RMG. I would assume CVD W is the most common way to fill it given you don't need to worry about shadowing, complex topologies, and that it is much faster than ALD. For GAA you have to fill W in places that can't be seen from above and I have to assume W fill would need to move to ALD W. I don't know enough about ALD to say for sure, but the complex 3D geometry might make it so PE ALD doesn't work and you need to do some low T thermal ALD to get inside all of those nooks and crannies.
Not really relevant since TSMC rarely converts fabs to newer process technologies. I also suspect that high tool reuse mostly occurs for sister nodes. ie 20nm/16FF, 10FF/N7, and N5/N3E. When you have to buy new equipment for your brand new fab anyways it makes no sense to use the old tooling unless it can do the job just as well for cheaper. Obviously in the world of memory or Intel's old pre foundry world, you want to maximize reuse. But TSMC'S business model doesn't heavily incentivise tool reuse outside of when process nodes don't have long decade plus volume tails.
My understanding is that you can't change depreciation schedule mid life. Intel 7 would have been ramped up in the 2019-2021 timeframe (pre depreciation schedule change). If most of that equipment was on the 8 year timeline I suspect the write down number would have been a lot larger. As is, most intel 7 tooling should have been near the end of their depreciation lifetimes.