I don’t think it’s an issue of pesticides being “too weak for consumers”. You can buy all the same stuff as an exterminator[0] (use PPE and follow the labeling, don’t break laws, etc), but when you spray you’ll notice a huge knockdown, hundreds will die, but it only takes a breeding pair to get right back to an infestation in a few months. Generally when doing roach infestation treatments you do a multi tiered approach, with max legal mixes of pesticide + growth inhibitors in your spray then putting down bait in spots that you DID NOT spray (or they won’t ingest the bait). They’re just resilient little buggers. Spiders are actually harder to treat, but most people don’t end up with spider infestations. And then bed bugs are in a class of their own in terms of awfulness and difficulty of elimination.