Do they work? Yes, they do. That "rat tail" is the 'other half' of the antenna taking the place of the HT's chassis which is what is usually the 'other half' of the antenna. It's still limited by the 'size' of the whole thing, there's no miracles involved here. A typical rubber-duck antenna is not a quarter wave in size. It can 'load' like one, but that doesn't make it a quarter wave, it's length does that. It's still a 'shortened', loaded antenna. The simplest solution would be to make that rubber-duck 19 inches for 2 meters, or about 6 inches for 70 cm, or whatever length for the band of interest (that "rat tail" too). Another part of the typical HT's antenna system is the user's hand/arm/body, it's coupled into that antenna system too. Lots of variations in that! The 'tune' of that antenna system is very vague, not really all that 'close'. And will change with how the HT is held/used. (Same for a hand-held scanner/receiver with attached antenna.)
The rubber-duck on any HT is for convenience only, not performance. Expecting good performance from any 'variable' antenna system depends on how it's used and situated. The best way of improving that sort of antenna system is by divorcing it from the radio, moving the antenna to a less 'variable' position. Those weird-o's with the antenna mounted on a hard-hat ain't so weird are they? Well, sort of anyway...
- 'Doc