sorry but I really have to disagree with that - the idea of an untrained mechanic being let loose on todays modern aircraft is pure madness.
No one has said anything about an untrained person. A mechanic is a trained person. The regulation stipulates that one cannot perform any maintenance function unless one has done it before under supervision, and been trained in the task, and additionally requires that the work be done in accordance with all approved data and industry standard.
At nearly all organizations in the US, specific training is available on any given type of aircraft...but no type ratings are issued, and none are available to be placed on the FAA mechanic certificate. The rating is unnecessary.
Not holding a paper rating doesn't mean one hasn't been trained. Operators, airlines, certificate holders, agencies...all insist upon and use mechanics trained on their aircraft.
We simply don't need a type rating on the certificate to crow about.