Yah... the thing here is that you DONATED to the server in order to help and keep it on. The perks are secondary. If we keep doing the Pay2Win it will get boring and boring as we on the higher ranks will get (and we have them already) things so easy that it will miss all the fun. As for the lower or non ranks will be so hard to keep up with the higher ranks that it will get so annoying and it will lose the fun. Giving players more vaults increase the time you can keep playing compared to someone who has no rank.
Well that's the thing, it influences people to buy more ranks. Like your said keeping the server going. I wish i could discuss this when it wasnt almost 5AM xD im getting tired