Curious what you are referring to. I often try to find the optimal calendar app, and while I know Fantastical isn't it for me, I am curious if there is an overarching story/reason why that I'm not aware of.
It was the typical subscription monetization move. Except the lack of hubris and overall tone from the developer after removing features that were paid for in previous versions put the icing on the cake.
Fantastical and Drafts were the two apps I used daily. The developer needing to get more money from me completely ruined my ability to use the app in the same ways I could previous, without having to constantly decline/ignore the 'upgrade' options that I'd actually already had previous.
It's then I knew, that supporting small indie developers is just as risky if not more so, than a large company. I've since never put my eggs into any app basket without seeing the woods through the trees and avoiding the inevitable.
It's lame from a social standpoint that subscriptions are fracturing the indie software user community. But, it wasn't paying the bills to have people half-using all the apps. You named two apps that have released features and improvements at a furious pace since they went subscription. That's great for users who are all-in and wouldn't have been possible if accommodating you.
Classic business-of-software holy war stuff. Some people were angry that Fantastical moved to subscription. They also moved Cardhop into the subscription for non-grandfathered users.
For actual users of Fantastical 3 and Cardhop 2, it's been nice to get new features without having to wait for a Fantastical 4.