true, what is your opinion about letting the node owner decide which percentage he wants to share?
Yes, I think we should have a mix of full archival nodes, DHT sharded nodes where the owner decides the percentage of the whole blockchain they want to download and share, and full pruned nodes, and SPV clients.
with a decentralized opensource system like bitcoin its just not possible to force anything about the user.
e.g. if my server could not save the share bitcoin-core wants to save/distribute there are only two possibilities for me: stop my node or change the code to the size which works for me
We cannot and should not force users to do anything, but can always build in incentives outside or within bitcoin core that increase node count and distribution. Some have already been discussed and some not.
so we both have reached consensus...
atm bitcoin foundation has a reward program for nodes (which is the reason i started mine - not to profit: i just realized they are needed atm, and i dont have a problem running it for the next years)
i would very much like any idea to add incentives to run a node - for validating and submitting transactions and distributing old transactions or blocks.