How do you believe so? I assume because enforcing strict transaction use requires more and more filters in the future? In that case you might be right. But I was referring to being conservative on the use case of Bitcoin. Not necessarily the code base. Although I would also be down to discuss and look for consensus changes to Bitcoin to keep arbitrary data out. I don’t know how and I too like the advantages of P2SH. But I like to think we have decades to think about this. That’s what I mean by conservatism. Not getting frustrated when seemingly good changes to Bitcoin are not there yet after years. That’s okay.
Discussion
No. Enforcing strict transaction use requires consensus change -> fork.
Decreasing the volume of spam might be achieved with filters. But does not enforce anything.
(If there is one miner with "custom" mempool filters the spam will be mined. Most of the miners are aware of config file on their node and want to get payed)
To enforce something on mem pool level means forcing every miner to use that mem pool setting.