That’s just the way we work with that engine, we’ve just update it not just replace it, and some point we may say there’s Source 2 or whatever, but really for us there’s been a pretty easy way to keep it and understanding the tools,” Faliszek said
This step seems quite valid, keeping in view the cost in terms of time, money and power, and if these updates can manage the demand of the developers, there seems to be no harm in it.
If you were hoping for a complete overhaul of Source Engine by the PC maestro, forget about it, at least for some time.
Source. PC Gamer