Engine thermals are added, why not include turbos? They also suffer from overheating. They also lower power if they got damaged.
Some turbos are thrusters. Is it the mods that you are worring about? What cars do you drive that face this problem?
That would be a nifty feature, however, there would have to be added proper Intercooler cooling only for the turbo and the simulated loss of power when overheated/damaged. Probably might happen, but the devs have more stuff to add/fix first, so don't expect anything soon.
Turbo damage is only coming from oil damage. Unless boost systems have their own oil and oil pumps and oil cooler systems (some of them do) there is no reason to expand much more, unless the game wants to simulate backpressure of the intake and the turbo butterfly effect. ............what?
There are thruster entities in the game, they are mostly used to make planes or floating vehicles (like the Hoverside, made by Bernd). As @DIESEL PESMA said, the turbo's in this game are in a nutshell, engine power adders which act according to engine RPM. Hope this clears out any doubts/confusion.