I don't understand what everyone's issue with the build block is. Don't like it, don't use it.
Its the fact other people use it to get quick resources (and make salvage ships useless) that annoys people, your argument is really not suitable for this. Not using build blocks for this purpose yourself still means that there will be people who just join a server, build block a station and now have 100k blocks in their first hour. If we want to fix economy long term we really can't let that happen.
My personal solution for this would be that a planet or a station has a block modification value. This is set when it's generated and by default is 0.
For each block taken off an object it's value decreases by 1, however the value cannot become negative. If you try to take blocks off an object with 0 bv(Block modification value) it will fail.
What does this mean? You cannot remove blocks using a build block on a planet unless you happen to have already built on it, then you'll get a leeway depending on how much building you've done. For a pre-generated station the results are the same too.
But when you first start a player made station it has one block and a bv of 0. Meaning everything on a player made station can be edited freely. It also means a sufficiently developed planet, (or one you've spammed your own blocks on) can be edited to an extent too. You should also have an option to set your objects bv back to 0 (making it impossible to scrap) for finished bases if you want the security of knowing that no fool is going to scrap the base while your absent.
TLDR: Idea
Block modification value, starts at 0 for a newly made object. Delete block = -1bv add block =+1bv.
Pros
No build blocking planets.
No build blocking generated stations.
The above two don't negatively affect the economy.
Salvager ships now have more use.
Also
however the value cannot become negative
thus if you put in the effort to salvage the part of the planet you plan to build on you can rebuild the location with the new structures built how you wish (while still being able to edit the planet somewhat due to it now having a high bv value)
Cons.
Some people might prefer/be too lazy to build salvager ships.
Some may dislike that it makes it harder to just buy a build block and get masses of resources from default stations.
This idea is the enemy of any lazy person pretty much since to do the actions we are trying to curve requires genuine effort.
Extra options:
If you could reset an objects bv to 0 you can save player made stations from being build blocked by faction members/spies you invite.
As an option give ships bv scores too, so now you cannot spawn masses of resources or ships in just to scrap them and add free blocks to the economy (as easy as before)