Your argument so one-sided that any non-sync users will categorized you as a fanboy. This new unwelcoming trend of categorizing Syncs users as fanboys and cultist has started to appear more and more in many posts of lemmy apps community. Why? Because you are not presenting the reality as seen by the general public.

The price is appropriate to the dev so it be able to provide a sustainable income for him due to the very niche market it serves. But for the apps market, for android or even iphone app store, the price is ridiculous.

We'll have to wait to see how is the strategic decision taken by the dev is the right one or will backfire. Can he not just keep his current users but also keep enticing new users with an app that is very good but expensive? Or will it deter any new interests for any potential paid-users that will end up migrating to other less-featured apps but cheaper? Or will other apps keeps up in-synced with Sync and be able to offer same features at cheaper prices, making Sync's prices to be even more ridiculous? The future will tell.

That world view requires one to have a back story on every purchase they make and is placing value on a story rather than a direct experience. Nothing wrong with that for you, but that's not a generalizable practice. Ultimately people are more likely to use the app, compare it to many other apps, and decide whether paying 3-4 more times what most apps charge for ad freedom is worth it to them. In my opinion the current pricing is preying upon zealots early on and market forces will likely drive it down over time. In the meantime it's enough of a sticker-shock to leave a bad taste in many mouths.