Probably not so much a conspiracy as a lack of effort in this area, Ciro. Yes, it is true (and very annoying) that it has been impossible to even modify (add, edit, delete) the content of a custom POI on recent generations of TomTom. I do not understand why TomTom believes that this isn't important. Many users create or add to their custom lists while in the vehicle and at the site where the new entry should occur. I suspect that TomTom believes that not enough customers used that feature on older models. It would not be so hard to add that feature. The proximity alert might be a lot more code, but again, I do not think that TomTom realizes how important proximity alert for custom POI can help some users.
The overall problem, as I see it, is that TomTom did not realize that it wasn't any one particular feature that caused the upward trend in their sales in the old days, it was the fact that whatever feature you might need, it was more likely to be on a TomTom device than one of the others ... because the TomTom had so MANY of them. By having a more fully featured device, TomTom could pick up all of the many 'edge cases' that their competition had ignored. In many ways, they have 'dumbed down' the feature set now to where my regular use model could almost be just about as well served by a Garmin.