Depends on what you define as "worked". As far as I know, flat feet can't really be cured. Along with flat feet, I also have a chronic pain disorder so without insoles or arch support I couldn't stand 3 minutes without feeling pain. When I got my diagnosis for falling arches 5 years ago, I started using insoles immediately. It took a few weeks of feeling a bit uncomfortable before I felt like they were helping, but they haven't cured me. If it's been around a month already and you feel only a little better, then that might be how it'll stay. For me at least, they only delay the pain.

For me my Mr Super Feet (the green ones) are more for stability than comfort, and to make sure I don't sprain my foot again. Before I started insoles I sprained my foot pretty bad, and I think I actually had dislocated one of the bones over my arch. The insoles for me are more prevention than anything else.

Mine never really "worked" for long periods of time, I just got my new ones and I'm still experiencing pain that I just work through, as in used to it.

I have custom super orthotics and have been waiting them for many years. Unfortunately, my foot issues are so severe that I still experience worsening chronic pain and can't stand or walk for long periods of time without extreme pain and discomfort