In terms of risk analysis, and bang for the buck, I believe it is the right place for us to spend money. I believe that widespread adoption of FLARM for gliders will save more lives than the equivalent amount of money spent on mode S. Not only that, but as I and others have repeatedly pointed out, FLARM is physically achievable in most gliders, whereas mode S Power and space requirements preclude it for many, as well as there being no EASA-approved installation schemes.
As I've argued in other places, I think it's a crying shame that a 1090ES-based system with FLARM's power and weight requirements has not been developed. There's no technical reason why 1090ES has to be too heavy, costly and power hungry. But you've convinced me that FLARM for gliders is a pragmatic solution in the real world, where regulation and certification are once again aviation's worst enemy. I'd draw an analogy with aviation regulators' failure to embrace GPS as a hugely cost-effective safety measure leading to the sub-optimal situation we now have with a proliferation of different UIs and cables strewn across the cockpit, and an overall sub-optimal safety situation. The market won out while the regulators were still trying to get their act together.
I have a simple response to airline or GA power pilots who think we should have interoperability between gliders and the rest.
I wonder if synergy is possible at the level of the receiver? Can we make a FLARM receiver that decodes and displays 1090ES (ADS-B out or Mode S responses) or a system of the sort that italianjon describes that can also receive FLARM output?