nostr:npub1a2cww4kn9wqte4ry70vyfwqyqvpswksna27rtxd8vty6c74era8sdcw83a

And that hardness of Bitcoin to change is realized by its decentralization; i.e. the number of economical regular nodes and mining nodes.

The threat for Bitcoin in that regard is diminishing numbers of regular nodes being operated and centralization of mining entities.

Insertion of arbitrary data tends to increase the equipment and operation cost for regular nodes; cost increase -> centralization increase. That’s the reason why any exploit for arbitrary data insertion can be seen as a threat in the long term.