Unreal intake manifold cost

It seems that a lot of guys get several project cars and for what ever reason they never get done, my dad used to say that's because they have to many irons in the fire. A good friend of mine took about 6 years to restore his 1968 440 gtx convertible, it was beautiful when he got it done and when he sold it he lost money on it. I always hear that people lose interest in their projects, I don't know if it's a money thing or they just got to much going on.
I know Guys that do several at a time, but they got room and cash. I've got my Duster... it's pretty much done, to my standards lol