Nothing against SCS Software and their work, but ETS 2 is for me definitely way more a game then a simulation and i agree with the reply from Joao Rodrigues. It is more a game just for everyone, for those who likes it more "realistic" and for those, who likes it more "simple", so it is a hibrid game and yes i am a experienced Player that played ETS 2 about 1100 hours already. OMSI 2 as example is already a simulation for me. Some reasons why:
-> No realistic driving performance
-> No 1:1 map (Of course it will take about alot of hours to drive a Budapest-Paris route)
-> No realistic sounds (There is still no gearbox sounds for each truck and i think, they are one of the most important sounds of a truck, because they are louder then the engine itself, when reaching about 60 km/h; In OMSI 2 by the busses you hear them perfectly)
-> No utils for the driver (Opening windows in the cabin is some one of them)
-> No realistic logistic companies except Krone, Schwarzmüller and Michelin.
-> No realistic economic simulation (They call this simulation, but i call this a Kindergarten System, that you also don't need anymore, when you reach Level 20-25 and have enough money; This one is more developed for beginners, but not for experienced players, because it is hard to start for a little time, but otherwhise you get to fast to money)
-> No realistic damage and leak profile (Not only automatic brake and engine breakdown)
Also i think, that ETS 2 is more based on the old 18 Wheels of Steel games, which they are also from SCS Software, but i anyways like to play this game, because i love to drive long routes for some hours.