You have summarized the problem of the Unicode emoji process so well, but I want to say that it is not the one-directional pressure. Vendors do not want to implement too many new emojis, so the number of new emojis per year is essentially limited (50--100 [1]). Vendors also do not want that other vendors don't implement their new emojis, so they do cooperate with other vendors and obey the rules set by the Consortium (e.g. no trademarks). It's not comparable to individuals, but it is not exactly possible for vendors to put any emoji to the standard as well.

[1] https://www.unicode.org/L2/L2017/17206-emoji-and-vendors.pdf