Unlikely LEGO will repeat LEGO modulars any time soon. If there was any possibility they probably would wait until they were done with the modular line and wait a few years.
LEGO is not into reissuing past sets (outside of Star Wars) except on rare occasions. The Toy Shop reissue was a surprise to me.
Part of the reason is LEGO also makes the sets to sell. In the past LEGO tried to do re-releases of old sets which I've read wasn't very successful.
LEGO Legends
http://brickset.com/sets/list-4672
While there is a lot of enthusiasm and interest in re-releases of nostalgic sets, it doesn't necessarily translate into great sales. AFOLs make a tiny percent (single digits I've read some places) of actual LEGO sales. If a set uses a lot of common parts in current production, it's possible LEGO could make a small run with little costs.
I concur that LEGO doesn't really care about the secondary market. LEGO does care though on people buying there sets. If it is known that popular older sets will be re-released regularly it could have a negative effect that people won't run out to buy sets in current release thinking they could buy it in the future. The standard collector practices fall in place.
In general there is a greater buzz and buying interest on new stuff.