Everyone has exactly the same amount of time: 24 hours in a day.
Every task that a person does means that there is something else that they are not doing.
To incorporate bug fixes sounds easy, but consider for example all the fixes floating around for "mkdir". Each one fixes mkdir for their operating system and their version of mzscheme, yet it's time consuming to ensure that a bugfix doesn't break someone else's installation.
When a bugfix has been tested and used by lots of people and there is a consensus that it is the right thing to do, then it would be easy for Paul to incorporate it into an arcn. When someone simply says "here's a fix!", then it takes a lot more time to figure out if it is the right fix and if it isn't going to make it worse for someone else.
This why the whole "network of trust" concept as it relates to massive distributed software projects is important. I'm sure if Arc will do well then PG will need to establish people whom he trusts to aggregate packages and give him only the good ones in order to cut down his personal time investment. Some guys on this forum are definitely knowledgeable enough and motivated.