Maybe you should get warned when you build too much bricks or something. Or you raise the hardcoded limit and set it in the config where everyone can change it with the message that it's your own risk.
Is there a way to stream the bricks or does the memory gets cleared when you go far away from the bricks?
The bricks are streamed. Memory is cleared when you go far away from bricks. But only 128k are visible to a player at once. I am not making any promises here. It is not high on the priority list to have more bricks than can be rendered by most players at a good framerate, and it is not something that we have spent a lot of time testing. So it may break in odd ways at that high of a brick count.
Servers often get to a high brick count, then the number of users drops off dramatically. This is because they can't render the world so they go elsewhere. For the Block Party this happens around 70k bricks, about half the available brick count. So in terms of practical benefit to users, speeding up the game will help more than adding more ghostable bricks.
32 bit programs on Windows only get ~2.5gb of usable address space, more or less depending on loaded drivers and other stuff. In addition you have to use some of that space for the rest of the game. The game will also invariably experience some fragmentation, or even memory leaks, reducing the available footprint still more. We could go to 64 bit, but again, most players don't have 64 bit systems. So it would be a lot of work to benefit only a minority of players. But right now memory isn't the limiting factor - it's performance.
The main thing that we are looking for with Blockland is how to get more users and keep them happy. The maximum builds are big enough for most people. There are other areas that need more work.
Anyway I am sure a minority of people will demand more bricks no matter what I explain, whether or not it reflects the majority of the Blockland user base. You are certainly welcome to complain, and to try crazy things to get past the limit, but until more servers start breaking 100k brick count, we probably aren't going to do anything about it.
TLDR: max brick count is plenty high for 99% of users, so it is unlikely we will spend months working on higher brick count just for you.