He is capable to work much faster than that but he is easy going plus he is not even thinking about to hire more help always making bs excuses like "can't find somebody who can actually draw like me" or "its to expensive" bla bla bla
I think you are at least 1,5 years behind the curve. DC's saying for a very long time now that he'll only get a second artist if the perfect person comes around and it's pretty much obvious that he'd rather like to finish the game alone.
So it's not like he's making any excuses, it's not like he's asking for more money and it's not like the speed has changed that much, when you actually take all things into account. In the end it simply won't matter whether he earns 30.000, 50.000 or 80.000, the speed will stay as it is and as it has been for the last two years.
Sure, people will bang on about it for the next 2 years, too, but at some point people will simply have to ask themselves, whether they are wasting their time complaining about this specific point.
Edit:
Does anyone know if DC will create a new game when he's done with summertime saga?
He was quite enthusiastic about his next project about 2 years ago (he even thought about hiring somebody to prepare the new engine etc. back then), but it looks he then decided to go all in for SS instead. Once we started getting better animations, the rig system, etc. he's hardly ever talked about new projects.
But sure, it's his job and he seems to have fun. So I don't really see why he'd stop as long as people want to play what he creates.