> If they were going to reboot the Zion construct, why waste time with a full-scale assault?

I can barely believe you ask this question while you gave the answer yourself. If Zion is not real, they are not "wasting their time" with a full-scale assault, as the machines making the attack simply aren't real either. It's a fake attack in a fake world to make the people believe it's all real.

There is another possible explanation though, still counting Zion as not the real world. It could be possible that the Architect and the Machines don't know that Zion isn't the real world. In that case, they're imprisoned within a Matrix as well, and Neo and Agent Smith are the first to escape this level...


Time will tell :-)