I've bought different kinds over the past 15 years, The quality on all of them can't be that bad.
I suspect them dying is being fed 12VAC.
The halogens don't have a problem with it, and although these G4 replacements should rectify the AC properly, I still don't think they can handle it long term.
So my next step is to replace the bricks with 12VDC
Apparently it worked, their advertising is now on the world stage.