Frogboy provided the funding for it, that could very well be his share of the workload.
It may be up to just the Civ 5 people to come up with everything technical.
He is still the CEO of Stardock and still has the responsibilities there to worry about.
As far as there being no tech demo, it probably hasn't even been completed yet. You can't just bust a brand new top of the line engine out in a few days of a few people's time.
I do want to note, though, that it's billed as a 64 bit engine which means no backwards compatibility with 99% of XP users and with a reasonable percentage of Windows 7/8 users. The developers usually make things backwards compatible to get sales from those lagging behind in OS technology, so this is a pretty bold move. It would also harm their ability to license out the engine to other designers as well.
There are, however, plenty of advantages in making such a move and especially being one of the early players in that space. One of the best benefits to making this move is that you can load a whole lot more into RAM, an amount only limited by the amount of RAM installed on the PC because it is inconceivable that a PC would have as much RAM as a 64 bit program can theoretically use. The big thing that cuts into that is the loading of graphics into a ready to display state, so they should be able to make games with high end graphics that still run really smoothly.
Also, support for 4+ cores and especially hyper-threading has tended to be lacking in other engines and there is potential that they can make games that can actually use all the processing power available to what is turning into the average person. A few years ago gamers crossed over the 50% mark and 3+ cores became standard replacing 2- core systems. Games have lagged behind in this transition, because a game designed to maximize a 4 core + 4 thread processor like a 2700k would just crush the processing power available to somebody using anything dual core with no threads. If the engine is going to be 64 bit only, a huge swath of the people with 2- cores are already ruled out of using games made on the engine anyway so there is a lot of reason to really bake in full core/thread support.