Stupid idea, are you just hate high level and want to doom them?
Seriously, get yourself up and build your economy, don't wait the TSO fix that for you !
You already pay time and expensive resources to build them what the idea to pay more for them !? logically you need 1 horse to 1 cav but you pay 10 as example.
For Cannons. do you have any idea bout how expensive is they?
Plus, you pay resources and gold and upgrading resources for houses, this this not enough to be called Maintenance cost?
Oh finally, what the joke that told you that players save troops just for show? the troops usually not last more than 24 hours before they killed in Battles of Adventures.