Blimey, I thought I was exaggerating for emphasis when I suggested that might be the case. I had no idea some projects were genuinely run that way. While none of us knows whether ED's development actually is managed like this, it would certainly explain much about the current state of the game if it was, especially all the niggling little missing features and annoying bugs that seem to survive through multiple builds.
I'm sorry to say but yes, some projects are run very badly. If planned well enough you would have a contingency built in to allow for bug fixes etc. However this is where feature creep can bite you if the fix will take longer then the built in safety margin.
Simple building site example: Bob is a plasterer, he's been booked on the 10th day of the project to come in and plaster the walls with two days planned to let it go off.
Frank, the electrician is due to finish his work on the 9th day but he has a problem and will need to come back on site to finish putting the plug sockets on the wall.
What to do? Put Bob off and also ring the decorators to let them know they are no longer required on day 13 but should start work on the 14th... They may be booked to do other work on that day. But if we let Bob in and then call Frank back to finish that means we'll need Bob back to re-plaster the wire runs... then two days for it to go off then we can call the decorators back in if they are available.
In other words, all it can take is one thing not to be done on time and you can have a nightmare on you're hands. Yes the work for the clock is rather simple to get done but in order to get it done right - do it at the right time
Then there is the other nightmare... you're bosses deadline for release but that's a pile of horse dung we'd better not get into!
Me personally I try to always have it so a few people will be free for a while so they can either pick up the slack or be put onto something quick like this. I always build an 18-20% time contingency into each phase of the project to cover creep and last minute additions.