As a landscape architect, I don't take any issue with gimicky hybrids. I actually would encourage growers to experiment with them.

Market pressures work on plant sales just like they do on anything else. If the hybrid is worth it's salt and performs as promised, and if that promise fills a need in the landscape trade, it will continue to sell and be refined. If it doesn't, it'll be relegated to the adds in the coupon mailers and the junk catalogs, which is where most of these end up, before becoming "extinct". (Tri-colored azalea, anyone?)

A home gardener may find pleasure in the fleeting bloom season of many flowering shrubs, and there is an art and great rewards to successional plantings that cycle through many specimens to provide continual interest. But there are also many locations and situations where a repeat bloomer is ideal. Coporate parks/office areas, campus living situations, even small public parks etc., are all areas where you want maximum impact from a plant. A short bloom season is a handicap in these situations, esp where there is not room (physically or in the budget) for a successional planting. Endless Summer is an excellent example of this. It's replacing Nikko Blue in many plantlists now because the small amount of additional maintenance is not an issue for a grounds crew, while the continual bloom is a big benefit.

The only downside I can see to this is the possibilty of older varieties not being available, as growers devote field space to the new hybrids. I doubt there's too much danger of that. For every client who wants the latest and greatest, there's another who wants only native, non-cultivars, as true to the wild form as possible. And heirloom plants have such a following now. I'd say there's plenty of room out there for both the tried and true and the new hybrids.