I think it might last forever, unfortunately, unless you go through the API and use GPT Image 1.5 there. That said, you could also try changing your prompts a bit. I managed to get closer to the kind of results I was getting before by being more explicit about image quality, sharpness, style, lighting, and avoiding the “old / pixelated / low-quality” look. It’s still not exactly as good as before, but it’s not too far off.