In theory no.  Because difficulty goes up based on current network hash as people join.  It should be believed that the same proportional number will join btc.  So the time for found should remain the same.  6 mins/block to the whole network.  And if btc hash remains the proportional as total network, it's at 50(something)mins/block here currently.  I don't know what the exact time is.

In reality it won't happen that way tho.  If more people join the network and less proportional joins btc (or none of the new miners) then btc will end up taking longer and longer.  That's why it's so hard for new pools to start off.  Getting people to join so it can hit critical mass and be large enough for people to stay.