I already mentioned some examples how to disincentivize it. For instance, some privacy coins drastically reduce the amount of publicly viewable data per transaction due to encryption of many transaction components.
Here's a minor but important thing to note: those particular cryptocurrencies you mentioned previously didn't begin with this feature, which appeared to be a trouble for some later on. And even if they did, removing it later should be considered censorship. Bitcoin on the other hand allows you to store data since v0.1. Second, as far as I understand, cryptocurrencies like grin and monero don't have the analog of OP_RETURN? Isn't that a serious disadvantage for forward compatibility?
I agree, they are very different in nature and it would be hard to use the same mechanisms in Bitcoin. Maybe they could be used just as inspiration and we could create something that fits Bitcoin and still lets us achieve the same goals.