Yes, it's seriously overpriced and storage costs hasn't decreased on Tarsnap for ages. That is the reason I am currently migrating off Tarsnap after using it for over ten years.
No. I already said it's probably not for you. If you need lowest price per GB and don't care about anything else including your time or customer support then nothing beats a bunch of google accs with free drive tier. No price is better than zero
But for me tarsnap is convenient as extra offsite backup for valuable stuff. Price per GB is not the only factor and different people have different priorities.