Yes, I have noticed this in my games also and I usually need to rein in my team mates. Sometimes when you have the advantage (in your case you had all the cards) with you, and breaching high ground is not possible, you turtle down - but offensively farm their jungle first (as 5, so you don't get picked off), farm lanes and push them in, take RS and wait for them to push.
Even if they farm your creep waves, they will be staved for farm and over time, levels also and in this case, abilities also (what good is an LC without duel damage?). You pressure them constantly, never breaching high ground, but coming tantalisingly close. Usually, at some point, their discipline will break down and they will either try a split push or a death ball - you wait for them to come to you, have sufficient vision, kill them and push.
Also, if you must push, ensure that ALL of you have BB and if possible BoT's - if you are ahead, this is doable. Get Rosh and then push. This will essentially mean a 11 v 5 (5+buyback+aegis) which should be sufficient.