i'm sure that there will be solutions found though... as it is, those blobs of data can be literally left out of a block without impacting the consensus, if i am not mistaken

putting hash sized stamps isn't going to cause a big problem, again probably just a matter of configuration options - if a UTXO can't be spent technically the U part is irrelevant, if you see what i'm saying, since it's unspent, but can't be spent

not sure if that is currently an issue in the sense that it's indexed, again, this is mainly implementation issues not something that really, long term, is going to impact the growth of the database or block storage

it's just a problem right now because the implementation doesn't quite reflect what the specification is

there is folk in the bitcoin dev community who are working on solutions

there is no doubt that the attack on bitcoin in 2017 caused damage, i think we'd still be at like 350Gb at this point without it