Availability of their existing dev kits is at best spotty. The AGX Orin [0] dev kit is at least available for backorder at $2k USD - but I haven't seen any of the Xavier kits available for many many months...
Yeah - strong supply constraints right now - side effect of what happened with GPUs... in the first half of 2020 Xavier devkits were very easy to buy at MSRP.
For Ampere, there has been the AVA Developer Platform ($5450, 32-core) recently: https://www.ipi.wiki/products/ava-developer-platform but that's not a cheap solution.
Given the history of NVIDIA, will be really interesting to see what happens there too.