I quite understand why early training has to be conservative with respect to practice height for a PSL but the reality is that 500' AGL really isn't good enough. It's much better than nothing, but there are any number of things that can kick in below that point; these all require practice in energy management, to use a contemporary phrase.
My flying background has not been exceptional but I think that some gliding experience, plus landing a variety of aircraft in off-airport landings (mostly planned!), has helped develop some useful skills. I completely agree with a number of posters who point out that, in challenging circumstances, the battle is - and should be - more mental (including decision making) than procedural.
I guess it's tough in areas of high population density but I've often found that instructors in rural parts of Australia have PSL-friendly paddocks and beaches allocated, or strips that are strips in name only. With the right owner permission arrangements in place, these are invaluable to the pilot who wants some help in going beyond the basics. Like all flying, messing up can ruin your day, but a total fear of planting a typical SEP spam-can in e.g. a good paddock is misplaced.