However, think about it this way:
Imagine investing $20,000 a month in supporting compliance, instead of Remicade. For dietary interventions, this could mean a nutritionist with weekly meetings, occasional meal-prep provided by a personal chef, and even weekly therapy sessions. This would still likely be cheaper than $20,00 a month.
We're willing to make this kind of investment with drugs, often without batting an eye.
Why not with other interventions?
I'm not sure about that. Non drug interventions that are effective, and not generally cheap. Consider that providers of those services are incentivized to capture as much profit as possible. If the alternative to there service is set to let's say arbitrarily $20k, they can probably charge in that neighborhood as well, or higher if the insurance companies can be convinced to pay more.