That's a bit hyperbolic don't you think? Sure, they're the only game in town when it comes to the leading edge nodes (eg. 3nm), but there's plenty of options at 14 nm and above. That corresponds to AMD zen (released in 2017) and Intel skylake (released in 2015). They're significantly worse than the latest and greatest CPUs today, but they're still in use today. I'd hardly call that as "going back to the stone age".