Well, they have discovered remanants of plants in royal, tombs that at that time only grew in current time Central-South America, and we know that
with their maritine technology, there would be no way to make it there.
Also I find it funny that even in the egyptian gov. story, the egyptian culture was bearly starting up (in the best case!) around 10.000 years ago,
How could they have possibly build those pyramids? and even if let's say they have built them, why not keep working on the technology? We can say
that that's what humankind does, once it discovers something, it keeps using it, builds it bigger, better, but here, we have these huge piramids, and
then hundrets of smaller ones poping up all over after the first big ones.
It just sounds like they came up with the current known history of egypt, and are looking for facts to back it up, and who knows, maybe hidding
facts that could prove otherwise. (sorry to say this but didn't the nazis do the same thing? / not saying that they are fascists or anything)
There are many organizations out there simply begging the egyptians to let the dig around the Sphinx, but they simply made a federal law there
that it's not allowed to do so, I mean come on, make a dig site outside the secure area, and dig to the chamber, anything...
By the way, I liked the underground complex theory, I didn't belive it was true from the begging, I for one think that the atlantians had their
own continent, and tried to limit interactions with the rest of the world only to trade, and the piramid design, and so on was just the rest of the
world trying to copy what they saw there... you never know for sure, but these are my thoughts about it. But hey, maybe we'll find out the truth