Well, I think your first question probably suffers from post hoc ergo propter hoc (aren't there MANY reasons for the Orthodox Church's dwindling presence both now and then?).
Ok, what are some of the reasons?

Your second question might just point to one of those many reasons for the apparent disparity.
Well, I guess I would have to agree, since I'm the one who offered it as a possible solution to the problem (I wanted to hear if others thought it was a solution). I don't think it's a very good solution, though. Some Fathers considered the prophecy about the Gates of Hades not prevailing against the Church to mean that earthly powers would not dominate the Church. But haven't earthly powers, at the very least, severely handicapped the Church for centuries?
The first part of your first point (Roman emperors persecuting Christians) I agree with, the the second part (about the local officials) I would disagree with. I've read more hagiographical texts than I care to remember which had the main plot as something like "Man wants girl, girl refuses, man trumps up charges and gets governer to kill her" or "Man wants property, other man refuses to sell, so first man promises civil leader half the wealth if they kill the Christian". The governers did indeed have great leeway... but I think they used it to their own greedy and power-lusting advantage.
Regarding your second point (Rodney Stark...), I hadn't heard it put in quite so systematic an argument before, though it certainly makes sense. Really, what you are saying is pretty close to one of Nietzsche's main arguments against Christianity in
The Antichrist, ie. that they pander to the "scum" (to use his idiotic word), the lower classes, the ill, etc..
Bizzlebin
I think you have too much of romanticized view of the early Church, Asteriktos.
I bet that's not something someone says to an agnostic every day!

But really, it's quite the contrary. I am fully aware of there being great falling aways and such. This is the reason that I added, "At least, that is the traditional way of looking at things"... because what I was saying was not my own position so much as the traditional position (not just of Tertullian, but of almost Church historians and hagiographers I've read) in the Church. Basically, the stories of the ancient world, and the historical reality of later times, seems to contradict one another. There is an apparent discontinuity, which could have many solutions. Maybe the early Church really didn't handle persecution as well as it is claimed by Eusebius and others. Or maybe the later Church just was too beaten down to put up much of a fight. But why am I giving you answers? This is what I wanted the
Orthodox to explain...

However, the revival we see in former communist lands, and even in the US, is this not the fruit you are speaking of?
Well, I don't know. You see numbers like 250 million thrown around for Orthodox Christianity world wide. That would include something like 80 million in Russia. But I've heard that only something like 3-4% of the population go to Church on a regular basis. Maybe 80 million have been
baptized. Maybe there has been an increase in people reading spiritual literature by 1000%... but when you start with small numbers, even a one thousand percent increase still leaves you with a very small number. Regarding the U.S., it's hard to tell since the numbers are so inflated. The figure often thrown around, of "5-6 million" Orthodox in America, is probably about as accurate as the 80 million in Russia. If you're talking about people actually attending Church more than twice a year, actually supporting the parish, etc., it's probably less than a million total. I'm not sure how much better that is than 50 years go. There have indeed been some prominent groups and individuals that have joined (the EOC and Jaroslav Pelikan come to mind), but there have also been lots of Orthodox from the old country dying off (here in western PA one can find a number of half-empty parishes, where the 40 or so people left are almost all over 65). There have also been quite a few schisms, the HOCNA one alone took with it twenty-some parishes.