1. Tire coating don't look as good as high quality dressings, but they last much longer.
This will depend upon the product. It is doubtful that you have tried them all. The product which we sell (which, for business reasons I cannot detail) looks a lot like a glossy silicone dressing when you first apply it, but it is totally dry. You would struggle to get much more gloss.
2. APCs or "Bleche Whites" (what is "bleche"?), are not sufficient to clean the tire initially if you want GUARANTEED success. Cleaning tires that have had a lot of previous dressings applied is difficult - even with the correct cleaner. Plan on a whole afternoon and more than 16oz of cleaner to do the job.
However, the correct cleaner can be diluted 1:1 with water and used in a foaming sprayer to go significantly farther.
This has not panned out to be true.
Without knowing what product you might have used and how, it is hard to comment. I know for certain that our primary APC will remove silicone dressings leaving them as I detailed. A risk, of course, is that an APC will typically have surfactants which can cover up, rather than just remove. If you fail to rinse adequately, you can think you have a hydrophillic finish and that the silicones are gone, but in fact the silicone is just underneath and then a coating on top may well fail. This is analagous to what happens when people put Dawn onto an LSP - lots of people think it strips almost anything but it doesn't, it just covers it up.