So those like you posting pics of MA numbers are lying? Prime time used to be evening hours in the US. 30 people flying in the MA at prime time does not suggest a subscriber base of 500+. I'm making an observation based on what hazmat said, no need to get defensive.
I'd suggest that you, as a non-player, lend very little credence to another non-player's "observations."
Most pix I've posted have been early morning times - and I'm more about balance than gross numbers. So there's very little for me to feel defensive about, other than non-players opining on things they have little clue about.

Evenings have generally been 90-110, fairly consistent over the past few years, but trending slowly downwards.
As for the total subscribers, only HTC has that accurate number, but one can get a feel, like I do, by not scoring in fighter category to see where # of players that at least had 1 sortie (and fighter is the most common, especially for any 2-week trials.) How many of those fighters are subscribers vs 2-week freebies is unknown, but generally you'll see more subscriptions than freebies, especially with the lack of marketing.
There are also seasonal variations.
If I were pressed to ballpark, and because not all subscribers play MA - some are just scenarios or special events, I'd estimate subscribers around 700-900 - above that 500 wag.
And considering the lower (and by now very stable) overhead, compared to the height of AH, this will still be profitable at lower levels than 500 subscribers. It just depends on how much time HTC wants to spend on rolling over tours, adding maps, enabling the winter snowmen, and dealing with the whinge calls/emails.
Many of the gameplay changes people agitate for are amenable to adjusting some already adjustable setting (like the recent NOE adjustment from 60ft to 100ft - but they do take time to implement and re-compile, and with lack of testing, carry the risk of messing up things which can make people leave faster.
There might be some issue with removing maps from rotation that we are unaware of and why so many unloved maps are still present (some of which have a direct impact on players willingness to play them.)