Some items do only run when you are logged on. but others are for a certain amount of time such as exp stones, charms, Eternal endurance, etc. These items run for so many hours or days. There are reasons for this. first is that say I have a 30 day res rune on me. that equates to 30 x 24 = 720 hours. Now say I'm logged in about 4 hours a day. that equates to
180 days or 9months of game play for what equates to about $15.00-$18.00 US. It simply is not going to happen in this case.
As far as NPC that sells res runes it simply is not going to happen and that reason is money. money is what keeps the game running for free. UM players are usually AP buyers and and playing UM requires AP items. IF NPC sells res runes yes it will increase the number of UM players but it will also decrease revenue for aeria games. plus could ruin the market in game. So simply your suggestions are not going to happen unless you wish to pay a monthly fee to play this game.