I've only broke one t-plate in the past year I've had my car. And here in the US (California specifically) we like big jumps
The T-plate I broke was on the car for at least 4 months and it was worn pretty thin from running on the hard blue groove tracks we run on out here.
And yes the newer t-plates have a little more beef on them.
There are several problems I see with a brass or aluminum t-plate. One is the possibility of having it bend on hard impacts....if the car can land hard enough to flex and break a plastic part, there is a good possibility you'll be able to eventually bend one slightly. The other, is on a hard enough impact/landing is that you will probably break the trans case where it meets the rear bulkhead and also may pull the screws out of the chassis where the t-plate connects.