Something I find weird is that this article compares a 9950x with two different laptop CPUs and concludes that performance has increased massively in the past few years. If you compare the 9950x with its two Desktop predecessors (released 2 and 4 years before), you see about a 6% increase from the 7950x and a 45% increase from the 5950x. So you should consider upgrading regularly, but potentially not every single generation. I think it makes sense to consider the performance and offer an upgrade when you see a 50% or so cumulative improvement. Everywhere I have worked has upgraded developers every 3-4 years, and it might make sense to upgrade if there is a massive change (like when Macbooks went to M-series).

As for Desktop vs Laptop, that is relevant too. Desktops are typically much faster than Laptops because they are allowed much larger power envelopes, which leads to more cores and higher clock speeds for sustained periods of time. However, there is always a question as to whether your use case will be able to use all 16/32 cores/threads in a 9950X CPU. If not, you may not notice much difference with a smaller processor.

Source for CPU benchmarks: https://www.cpubenchmark.net/compare/6211vs5031vs3862vs5717/...