I mean, yeah, obviously the dev would rather people pay the subscription when some of the Ultra features require server work and/or continued costs (translation, OCR, etc.).
Developing Sync is his full time job, which is why it initially shipped without a lifetime tier. People voiced their opinion and the dev listened by adding the lifetime option and the ad free option. If you don’t like the pricing, use a different app. Nobody is forcing you to use Sync. LJ doesn’t owe you the app for free (or any price outside of what he feels is fair).