While I understand what you mean, Greg (as that is what we OO believe, too), I feel like Catholics would say them same things that you wrote about their own masses and church, despite having made many changes to both over the centuries. So, respectfully, I'm not sure that explanation actually shows how Orthodox and Catholics differ on this point.
It might be easier to just say that liturgies have developed
organically over the centuries to reflect the unique theology, ecclesiology, and history of a given church, but within the boundaries of comparatively few models based on the Christian worship of earliest centers of the faith. This is why there are many variations on the worship of Antioch (Syriac of various flavors, Greek/Arabic uses for the Chalcedonians, etc.), but there isn't a specific, organically-developed liturgy for, say, the Congolese -- only adapted musical settings of the Latin mass that was brought to them by the Europeans:
To 'write' an actual liturgy would involve (re-)writing and (re-)arranging the different parts of a liturgical text itself, not just putting the existing forms to new tunes, or adapting them for a Christmas dinner or whatever JJM is doing, wouldn't it? For instance,
according to wiki, the Catholic uniates who come from the Nestorian/Church of the East tradition and use that church's Anaphora of Addai and Mari have inserted an explicit institution narrative into their liturgy (presumably to appease/ape the Latins?), where there was not one originally. Some people also argue that this is what the Latins themselves did in creating the Novus Ordo/ordinary form of the Latin Mass in the 1960s, though I don't know enough about the history of the Latin mass to know how true that may be. The point is that these would be inorganic developments, created by committee or possibly even instituted by individuals, and hence light years away from how Orthodox approach their liturgies. After all, the Greeks had some flirtation with organs in America in the 1950s and 1960s, but that didn't make their liturgies anything other than what they were, because their order, textual integrity, and of course the theology, ecclesiology, Christology, etc. expressed through them would be the same. Which is another thing that Roman Catholics would probably say about their new mass or the tinkered-with East Syrian liturgy of their Catholic compatriots -- "but it expresses the same truths, so what's the problem?" The issue is organic v. inorganic development. As a counterpoint, there have been some changes to the Coptic liturgy over the centuries (e.g., the inclusion of the cymbal starting around the 12th century or so), but these are likewise organic and explainable by looking at the historical circumstances of the Copts at that point (from what I've read and been told, it was around this point that the Coptic language was definitively lost by the people, making the cadence of the chant itself too difficult to follow because the new language, Arabic, has very different stress patterns, so they began to use the cymbal around this point to keep everyone on beat; it is meant to be used essentially like a metronome, rather than an instrument, and I have personally witnessed priests admonishing younger deacons for being too fancy with it). We didn't start using it to appease others who already used it (there aren't any others who use it, to my knowledge) and wanted us to conform to their ways, or because we think it sounds nice, or to nativize a foreign liturgy according to the customs of the people (as in the Congolese Latin mass video above), etc.