no it doesn't last more than a year, but hey, I have no problem servicing/lubing up the brakes every year (scion tC here). But at least it didn't cause the sliding pin bushings to swell up like the silicone the dealer used way back in the day. Had to replace all those bushings because of that but never a problem with the correct grease..
I wish it lasted longer but hey it doesn't and I never have had a problem using the Toyota rubber grease. If that means less problems for me, then I'm happy..
EDIT: read your post claiming it doesn't survive heat.. It does but only a year. I have high performance carbon/kevlar pads that liquified the regular white shim grease Toyota uses! Had to go to the Permatex Purple ceramic solids grease and that doesn't liquify on the back of the pad/shims! But.. the Toyota rubber grease on the sliding pins did not liquify so yes it does survive high heat, been seeing that for years on mine.