Sales is amazing but if your companies sales people require engineering to build POCs a lot of the times or always have to sell some custom solutions, then it wastes a lot of resources and it usually indicates the company is losing product market fit.

That is true. My current work is in bespoke environments with mainly non-technical buyers who have been burned in the past. Our POCs are pretty minor lifts to build credibility and have worked extremely well.

If you're working in SaaS or commodity products and have to run POCs a lot, you're totally correct.