I think the initial purchase price is a bit high considering the lack of documentation and the reliance on users to support other users. But not by a lot.
The upgrade pricing is fine.
I do buy other software, but don't upgrade to the major versions as often because they cost too much. If I don't need the new features, I don't upgrade. Things like EaseUS backup software, VideoReDo, Debut Video capture software.
I also think a once off purchase, with optional upgrades, is far cheaper than the "free software" model, where you can use a crippled version of the software for free, but if you really want to do anything with it, you have to pay, or worse, subscribe. Games on phones, Free! But to play them seriously, or not just get thrashed every time, you need to do in App purchases, which can add up to many times the "value" of the software. A lot of those games can end up costing hundred of dollars, for a gaming experience that would cost about $60 to $80 on a PC. That's why I don't do in App purchases, or play much in the way of games on phones.
Then there are useful App like Endomondo, which you can use for free forever . . . if you like having a flat phone battery all the time. You used to be able to get a once of purchase to fix that, but now you have to go Premium, at US$6 per month, or US$30 per year. Plus they will keep charging every period unless you stop it, and then the software doesn't work anymore. You are dropped back to basic functionality.
Then look at Adobe Creative Cloud. US$10 per month for just Lightroom and Photoshop. US$50 per month for all Adobe Apps. Much cheaper than it used to be to purchase the standalone applications, but still not cheap. But it does have great documentation and Adobe support, and lots of third party training, assistance, and documentation, as well as lots of functionality add-ons.
So overall, MC is about right. Don't even think about going to a subscription model that requires continuous payments to be able to continue using the software. Or "in App" purchases to add functionality, unless they are plugins, JRemote, or similar. I don't think a free version of MC would work very well either, since any crippling would detract from the value a lot.
I think if you want to get more conversions from trail installation, you might want to try a longer trial period. There is so much to the program, and so many people want to use it "their way", that it takes a while to learn and evaluate. Some people seem to purchase in a couple of weeks, but others seem to buy at the last minute, and still haven't worked out how to use MC. You are probably losing people who give up when the trial expires at one month. But you have the numbers, so you might have a better idea about that.