If ARM comes anywhere close to viable enough to be "winning", there will be a good market for dev platforms, and somebody will step in and fill the need. Heck, some are even arguing here that the Pine64 already meets that need.
* New systems languages with promising levels of adoption
* Stablization and commodification of the existing platforms, weakening lock-in effects
* Emphasis on virtualization in contemporary server architectures
* "The browser is the OS" reaching its natural conclusion in the form of WASM, driving web devs towards systems languages
All of that produces an environment where development could become much more portable in a relatively short timeframe. It's the high friction of the full-service, C-based, multitasking development ecosystem that keeps systems development centralized within a few megaprojects like Linux. But what is actually needed for development is leaner than that, and the project of making these lower layers modernized, portable, and available to virtualization will have the inevitable effect of uprooting the tooling from its existing hardware dependencies, even when no one of the resulting environments does "as much" as a Linux box. The classic disruption story.
Why is this discussion so fixated on having a local development environment? It's 2019.