Actually, the RAM is not owned by anyone before somebody buys it. It is not owned by Block Producers or anyone else.
When you by RAM you stack EOS Coins. This is similar to say that you exchange RAM for EOS and vise versa. This happen in a closed system. i.e you only exchange RAM with EOS and you cannot exchange RAM with any other coin directly.
The bad thing I think about this is that the early EOS investors got 0 RAM. And some early investors, like me, feel bad about this. Because, we expected that once EOS is up-and-running we can any time start developing on it. But it turns out that we have to buy something additional.
Additionally, DApps developers (and I am one of them) is now not incentivised to develop for EOS because they have to buy EOS coins in addition to RAM for a considerable price. However, the price of RAM could go down, if a side-chain is established or if RAM could be added to the main-chain. But this is not enough from my point of view and the RAM model still needs more enhancements.
The good thing is that EOS will continue to evolve and it is designed to overcome any issue. And I hope the issues in the RAM model at Dawn 4.0 will be resolved in Dawn 5.0. Just like how Dawn 4.0 was better that Dawn 3.0.