The Grammar-Translation Method - Pushback against the consensus here

Salvete omenes

First, please don't view this thread as an attack, but rather a questioning of basic assumptions in this subreddit. In too many subreddits there is often a consensus that is developed by the users that sometimes results in gatekeeping due to every idea outside of the consensus being viewed as heresy and unacceptable to being posted.

While I do not at all wish to accuse r/Latin of this, please at the very least view this as an exercise in questioning basic assumptions that many of us (including myself) have held.

We often hear that the Grammar-Translation method is horrible and inefficient and doesn't teach one Latin (or any language) and that this is backed up by the latest research.

I wish to counter the "latest research" by pointing to the fact that the Grammar-Translation method (specifically double-translation, in addition to elements of the Natural Method, which I will get to in a bit) was the primary means of initially teaching students all across Europe for literally hundreds of years and to this day is promoted by polyglots on YouTube. I don't care what modern research says when we literally have hundreds of years of data from countries all over Europe.
Add to this that when this method was being taught (roughly 15th to 18th centuries), we witnessed the highest level of Latin since the days of the Roman Empire itself, which shows that it obviously worked.
Who here learning purely from the Natural Method has been able to produce advanced works in physics and calculus using Latin alone?

How did they learn Latin? The method was very simple:
1) Take a Latin text (starting off easy like passages from the Bible) and translate it into your native language (say, English).
2) Wait a bit until you forget and then take that English translation that you wrote and now translate it back to Latin and see how well you did by comparing it to the original.
Then move on to the next sentence/line/passage and slowly increase until you are translating entire pages.
Once you get good enough, you would be expected to produce orations and essays in Latin and be speaking in Latin with your peers. Proponents of the Natural Method will cling on to this as proof for their method, however they skipped the first step of the "double translation" method, which quickly makes you very adept at working in both English and Latin (having to come up with the most accurate word for each language) USING AUTHENTIC TEXTS (not fake Latin made for textbooks).
Remember, when you are translating from English to Latin, you are actually producing Latin, way more than answering small questions in a textbook, plus you are expected to produce a much higher level of Latin since you have to get it close to the original text.

(I do not wish to overly encumber this post with sources for everything as I expect much of this to be common knowledge in the Latin space, but if you want just a small example, you can see the curricula of Eton back in the day:
https://dandylover1.dreamwidth.org/99443.html)

The result of using only the Natural Method is what we see in this subreddit, with many students studying for years and even completing all of the Ørberg books, and yet struggling when they get to something basic like Caesar. They can speak in basic Latin on familiar topics but again struggle with native texts because they have been working with artificial texts this entire time. Whereas when you're dealing with authentic Latin texts from Day 1, it's not as much of an issue.

So my point is let's not be so obsessed with modern research and a modern style of learning when we have hundreds of years of a method (double-translation followed by yes producing Latin by speaking and writing) that produced the highest level of Latin for over a thousand years and thus frankly produced better results that what we are seeing today.

(the issue is that by the end of the 19th century, they started more focusing on translating rather than producing and today we are more focused on swallowing a massive amount of Latin without having the foundations very well set and thus neither method appears to be as effective as what we were doing from roughly the 15th to 18th centuries).

I look forward to your engagement, since the goal of all of this is to come up with the best method possible for learning Latin.

Valete