Smudgethecat is on the money, although approvals are issued by the Part 145 company they are on the basis of the engineer's Part 66 licence and type approvals. No licence/type rating, no approval to stamp.
Arguably base maintenance is on the decline in some countries due to the lower cost of doing it in places like the Philippines or Estonia, but there will still be a need to keep engineering capabilities close to base, even if it's only line and defects work. On a bigger subject what will happen to the airline industry as the oil becomes increasingly scarce and the price of fuel goes up? For sure rising ticket prices will shrink the industry reducing the need for work, but on the upside it will be more expensive to dead-leg an aircraft halfway round the world to be fettled.
Overall, I'd say it's definitely not dead now.... in years to come who knows where it will go, but then in these turbulent times who can be sure of the prospects for any job?