somehow u r right but not quite. if deed cost expensive from vendor would you sell it very cheap knowing you can do it only once? also it can be done by professional architect or whatever skill called, mechanic or something. so not everyone can create blueprint copy out of your house. this of caurse means that if you r owner you must pay architect for cfating a blue print. also this mechanic can be added - vendor deeds cost extrimly expensive price. this way only copied blue prints will be on market and devs can do it not only once opportunity but several times from one house maybe 5 times in general or 1 blue pring every 3 month of real time. and it only top architects could do it, well depends on house tear of cause. this way devs will create a private market of deeds and no one will be buying of vendors but no one will be selling it for 1 gold either cos this is subject of value. its rare. someone befor you bought deed for 10000 gold why would he sell it for 1 gold its stupid. also its produces it self like every 3 month so its rare. eventually market will be overflown of cause but devs can make it like if your deed havent been used withing 3 month then its disappears. so u must create a new one. this way you will always have one deed on you unless you sold yours but in 3 month numbers of deeds wont double or triple and price wont drop down. market will remain stable.
besides as i know house deed cost like 150 gold. u can make these money in two hours so this is already too cheap so its must be veeeeeeeeeeerrrry expensive and have system like im suggesting