Some comments… (In a random order.)
“1. Danger of abandonment”
I would think subscriptions would lower the risk of this? Because recurring revenue would make it possible for the development to be sustainable.
“4. The nagging feeling of a returning cost/ongoing issue.”
We have to separate what an app/service cost, and how it’s paid. Like, if an app costs $10/month, paying for a year upfront might give a discount, so $100/year. Buying something “for life” should also give a discount, but what would be a fair price? If we expect a lifetime of five years, how much is fitting? $300?
It’s just a bit weird to me, that everyone is hating on paying $10/month, but love to pay $300 for an undetermined amount of time and where you don’t know how well the app develops (if at all). 
Now, some might say “No, I want to pay $30 for life”, and that’s fair. But the main thing you’re asking for then is cheaper software - and that’s an entirely different discussion. Like, then we could flip it around, and go back to that I don’t think $1/Month and $10/year is that terrible either.
To me, this thread seems to mainly be about spending less money on apps - and that’s completely fair! My point is that I think the whole “subscription” angle is a bit flawed.
“2. Taking my data hostage. I dislike having my data in their database and format. Often the claims of easy export are more cumbersome than promised. Then devs or VC behind the startup wants ROI and increases prices at will.”
This brings me to this point.
I hard agree on this. And I only use apps that deal with regular files, for this reason. But if this is relevant at all, isn’t it more of an argument for subscriptions than against?
Like, let’s say we have an app, that does have easy export. And I can choose to either pay $10/Month or $300/Life.
Then, after a year, I found out that I don’t need it anymore, found something I like better, the developer didn’t update the app enough, or something else. If I paid a subscription, I’m out $120/$100, and I can stop paying if I want. Also, if I email the developer, they have a real insentive to keep making me happy.
However, if I’ve already paid $300, I won’t get any of that back. I can’t “stop paying”. Also, doesn’t the developer now have less insentive to keep me happy, as they already have all the money they’ll get from me?
Like, I’m not saying everything should be subscription. I just think some of the criticism is a bit short-sighter, and mostly conflated with thinking software is “too expensive”. (Which a lot of stuff is - but as I said: Different discussion.)
Now the elephent in the room here, is: “What happens when I stop paying?” And the biggest problem with subs, in my mind, is that Apple doesn’t allow for developers to keep giving access to the app (but without updates) after you’ve stopped paying. There really should be a system like “if you’ve paid this amount, you “own” the app enough to keep using it, without updates, after you stop paying”. Nova has the perfect model I guess, where you pay $100 for the app + a year’s worth of updates. And then you can pay another $50 every year you want an update.