Mine did nothing for a whole month, then they took off.

I'd say it's a good idea to figure out whats wrong. Then even if the pepper plants are shot, you won't make the same mistake again.
-Mark

We had a similar problem this year. Mom out of desperation did the Epsom salt water trick and they started producing again. Still not big like we like but producing.

peppers seem to like fertility. Give them some fertilizer.

peppers love water. irrigate irrigate irrigate.

I applied a mixture of MiracleGro OG, Alaska Morbloom, and soluble azomite.
I gave it a mycorhizae drench. I put down driptape and mulched with straw.
I pulled out a bunch of twiggy plants.

It sounds like you did most everything right and they should have done fine.
For some reason the plants didn't root well and thrive so i'd look into the soil ph (most likely) but also if there was anything feeding on the roots, like symphylan. Also drainage, cool soil (straw mulch doesn't help) and various pepper diseases.

-Mark

I'm noticing that we are getting red ones now, and with our cooler nights (in the last few days) I'm expecting a possible early fall.