It's the economy.
Some of those Russian billionaires are no longer
billionaires due to the worldwide tanking economy.
I believe it was at least one of those 'former' Russian billionaires
who seriously considered taking up the offer to spend
200 million dollars to become the first 'lunar tourist'.
Now with billionaires worldwide losing a large chunk
of their wealth in this economic downturn, it's hard
to say if that 'lunar-tourist' spot being offered
by Space-Adventures Inc will be taken up by anyone
in the foreseeable future.
Wait and see I guess.