Earlier quoted context omitted.
Single core performance has not been stagnant. We're about double where we were in 2015 for a range of workloads. Branch prediction, OoO execution, SIMD, etc. make a huge difference. The clock speed of a core is important and we are hitting physical limits there, but we're also getting more done with each clock cycle than ever before.
Doubling single-core performance in 10 years amounts to a less than 10% improvement year-over-year. That will feel like "stagnant" if you're on non-vintage hardware. Of course there are improvements elsewhere that partially offset this, but there's no need to upgrade all that often.
Especially when, in that same time frame, your code editor / mail client / instant messaging / conference call / container management / source code control / password manager software all migrate to Electron...