Owner...
Here's the deal - Once you buy a deed you are considered the "Owner"
The monthly mantenance fee is just a fee to access the estate, not really rent, even though Marco himself sometimes mistakingly calls it rent on occassion here in the forums.
If it was rent, it'd be more like the real world where you only pay two months rent at most when you get the place, not the high amount that is paid for the deed on auctions these days...
The confusion arises from the fact that the deed holder is an "Owner" and the estate terminal does not list the new Owner until the deed holder claims the place... so Marcus looks like he owns a lot of places, when it's really some unknown avatar that owns it that just has not claimed it yet. This system is HIGHLY FLAWED because it makes it appear that two different parties "Own" the place... could lead to issues related to reputation if the new owner is purposefully not claiming the place to make the old owner look like they are a bad person for not paying up or something like that... I honestly have no idea why MA does not just have the estate terminals auto update when new holder has the deed - at least that would let everyone know who really owns the place so potential buyers would know who to look for if they wanted to buy the estate...
A time or two I've attempted to start listing who's listed on estate terminals and compile a list from that, but it's really a pointless effort since the info is really false info about who owns what, and it'd all be outdated anyways if the new owners ever claim the place and/or sell the deed to someone else.
It's sort of weird that Ownership is certified with the deed, but EULA - another bunch of words on a computer screen just like the deed - specifically says that no one in game can own anything... could eventually be grounds for a lot of various lawsuits and stuff... old owners sueing new owners for defamation since it looks like old owners did not pay up, both deed holder and old owner claiming Ownership of the place - although that could quickly be resolved by just claiming the place, Estate Holder Sueing MA if MA ever goes under since the deed is really just as contractually obligating as the EULA in some folk's eyes...
To fix the problems, MA should make estate holders have some more advantages then they currently do so more folks will want to pay the monthly fees... Perhaps make voting a reality in game by implementing the voting booths again, and make only those that have an estate that's had that month's payment done able to vote on things... Maybe make paying the monthly fee have an impact on how much loot you get. Maybe set aside some of the taxes in places like Omegaton and Genesis that have no participant owner collecting those taxes and use that with the above mentioned voting to get the money going in various directions to increase traffic in the local places. Maybe have more actual in game interior decorating contests with actual prizes that are worth winning. Maybe have more art contests in game, but require that the signs be inside of the avatar's apartments instead of having to be handed to MA to put in Oxford... Perhaps make it local competitions, where Omegaton is one month, Genesis the next, CND the next, etc... Maybe give better gifts on holidays and stuff to estate owners then has previously been given, but only if monthly fee is paid for that month - not just decorations, lets hand out stuff like eon armor, etc. Imagine how many apartment owners will be sad about not paying the rent that month, lol. Do similar for shop owners - instead of eon armor, maybe it's a gigantium or megaview sign (P,C) - the one that uses only one item point and is worth around 500 ped, or something similar? Maybe make it so that the travel fee to your home planet is free, but only if you pay up the rent last month, so you only have to pay for travel one way, and are free to come back so you can pay your rent for this month.
Maybe certain really nice quests that have really awesome limited time prizes can only be done if you have a deed and have your monthly rent paid up.