My guess would be the latter. Ingenuity was primarily a technology demonstration whose failure wouldn't impact Perseverance's main objectives, so the risk was probably acceptable.

As for launching several cheap, redundant probes - I think the biggest issue would be the cost of the scientific instruments. I don't have the background to know how much money could be saved you by using commercially available equipment. The basic scientific requirements might be too specialized for cheap commercial equivalents to exist, though maybe not; I really don't know.