I don't know about what percentage of programmers use perl or what percentage work on web apps. The only experience I have to base my decisions on are my own and my own experiences says that cycles and architectures 'do' matter.

I've spent my life counting cycles. In my field cycle counts often determine whether an an idea is producible or whether one is a no-starter. Yes processors are always getting faster but many applications have other constraints on processor selection and products have to ship with the processor available 'today' and the market won't wait for 'next-year. Once your processor selection gets outside of the commodity processors Moore's law often operates in fits and spurts. I often design with processors that won't be available for 9-16 months. Waiting for generation II would put production out beyond realistic business planning cycles.

Yes, historically such cycle limited code has been written in C or assembly but the same forces that have made Web apps independent of language efficiency have made dynamic languages like Perl available to the hardware designers and embedded designers. These designers 'do' care about cycle counts.