Adobe is primarily focused on business users and people who use their products to make money. And their products pretty much set the standard in photo editing. They also lost some users going to subscription.
Spark is nice, but it’s no Adobe. And it’s one app. Better comparison is Fantastical, which did the same thing some years ago. Now they often discount annual subscriptions by up to 50%…
There isn't a developer alive of any software that would turn down a business client in order to take on an end user. Not one. They may not admit it in as stark of terms, but it is the reality. Depending on the software they develop, that may be easier (Adobe) or harder (Spark, Fantastical) for them to make that distinction, but as end users, we shouldn't be surprised when they tailor their pricing or software structure to be more favorable to business clients.
I did some Googling on your assertion that Adobe lost users. Obviously, the only way to know this for certain is to work for Adobe, but I found nothing that supports this. To the contrary, Adobe has done gangbusters over the last ten years, while semi-worthy competitors like Affinity continue to struggle. Pricing structure appears to have nothing to do with it.
This brings me to something that is always on display in threads like this: Predictions of doom and gloom for developers who adopt subscription pricing. The big "push back" is always right around the corner, and yet... it never actually materializes. Developers large and small move toward that model (many, on our platforms of choice, as a result of Apple's unrelenting pressure). I have no idea if Fantastical has more or fewer users now. I have no idea if Readdle, developer of Spark, has seen a large number of signups for Spark's subscription offerings. What I am willing to predict, however, is both companies, and others like them, will continue just fine post-subscription transition and, assuming they've positioned their subscription offerings appropriately,
will do better financially then before.
Software development is a business, not a popularity contest. I'm not a software developer, but I do work for myself and I do have clients. Clients who pay me quickly and don't complain about my pricing are worth gold. Clients who love me but take forever to pay or stiff me entirely are worthless. I'll drop the latter in a heartbeat.
I'm not saying everyone should love subscription pricing. Far from it. Vote with your wallets, as we all should. I fully respect everyone's decision in this regard and don't mean to position my arguments to the contrary. But this insistence that there's some moral evil in subscription software and that there's this groundswell of public opinion that will reject it is not rooted in any reality I am aware of.