Couldn't you say the same thing for shares? You bought some shares for 5K, you sold them for 10K and now if you want to buy them again you have to pay 10K. Does this mean you didn't realize any profit on your 5K investment?
There is no law that says you need to buy a house for the same price, most people will either downsize or upsize anyway.
But hey we can be generous and say you get to sell one house without paying CGT in your lifetime. Would that placate the masses?