Touchy subject...
My 2 cents worth:
As a former Cubmaster and Scoutmaster, I understand what you are saying. In my area, we always agreed that getting a boy into the Cub Scout program was the priority. We did ask that they show up in a Class A uniform shirt to all events unless class B was specified for a particular event. I think the issues are cost, durability, boy's growth and honestly will they stay in the program?
Uniforming at the troop level was such that no scout above second class could request a scoutmaster's conference unless he was in complete class A uniform. That gave the parents time to get the pants and gave the boy time to figure out if scouting is really what he wanted.
I have to mention that the complete uniforming issue for every scout at every meeting did cause a huge blow-up between the existing leaders of what was the best troop in the district and some parents of new scouts. The parents (committee members) insisted all scouts should have all of the uniform for every meeting totally disregarding existing and very successful troop policy. They left and started their own troop. That rift started almost 10 years ago and is still existing today between the troops.
I am telling you this story because I don't want you or your boys to suffer the aftermath of such a rift. The boys are the ones who actually loose in such a conflict.
Worry about the complete uniform for the boys later.
I believe adult leaders should always wear the correct uniform when they are around boys. My pet peeve is cammo pants! I actually saw a leader not to long ago wearing military cammo bloused up around military boots at roundtable. I was really glad I didn't have to deal with him.