Irradiating enough to kill cyclospora oocysts would ruin the lettuce though.

It seems the studies that have been done indicate pretty high dosages required for noticeable damage to occur and that even then it can be minimized with packaging changes and care:

https://staging.billmarler.com/blog/pros-and-cons-of-commerc...

At the 1.0 kGy level required to effect Cyclospora, little difference was noticed in lettuce packaged in MAP instead of air, but some browning in air.

Food irradiation is a topic with depth. Spices are irradiated like crazy because there's no nutrition to nuke and they are insect fodder. Irradiation can be a continuum across food types. I'll bet a heavily nuked Pringle is indistinguishable from an unnuked Pringle except perhaps for improved phosphorescence.