Except most devs don't have any idea of what to do with them, and they end up mostly managing OS processes, containers, GC and JIT background processing, VM instances.
Maybe for 64 that's true but for mainstream usage getting 8 cores in a laptop instead of 4 is a massive gain. That's effectively what has happened in the current laptop lines with AMD having twice the cores with the same power usage and single-thread performance. Here's the comparison of the top-spec AMD and Intel CPUs available in the just released T14s:
If your workload is running a single-app that may be underused but particularly in home-office mode I'm constantly doing VCs, having 4 or 5 browser tabs that are heavy, Office for documents, etc. It doesn't matter if all those are a single thread, I'd be filling up the 8 cores and probably taking advantage of the 16 threads from SMT as well.
All Intel options on the T14s are 4 core. The only other AMD option is still 6 core. The slower AMD part is still twice as fast as the fastest Intel chip:
Your contention was that the extra performance provided by AMD was not usable, not that it wouldn't win in the market. So we were indeed discussing who had the best tech, even if that's not all that matters for commercial success.
Because those things go hand in hand, the large majority of developers aren't doing HPC, Fintech or work at FAANG, or even posting on HN and Reddit, rather they are the so called "dark matter developers" whose applications must run on those Core i3 and i5 used by the consumers at large.
As such most developers only bother to use what they already know and take very little effort for adding any form of parallelism or concurrency to their applications.
Android and UWP since the start have taken architecture decisions that forbid synchronous code, because both companies came to the conclusion that if that would be available, the developers would write single threaded code as they have been doing for years, so they took that option out of the platform.
https://www.cpubenchmark.net/compare/Intel-i7-10610U-vs-AMD-...
If your workload is running a single-app that may be underused but particularly in home-office mode I'm constantly doing VCs, having 4 or 5 browser tabs that are heavy, Office for documents, etc. It doesn't matter if all those are a single thread, I'd be filling up the 8 cores and probably taking advantage of the 16 threads from SMT as well.