You're blaming steembasicincome for general decline in STEEM prices? When the program started, STEEM was at close to 10 and now it's at 2.50.

The most important factor in upvote value is Steem prices. But check your original posts against your current posts and see if your rshares from steembasicincome have decreased. That's the only way to isolate the merit of your comment.

And don't forget to factor for your posting frequency, because SBI shares are valued on weekly basis to deliver consistent value independent of posting frequency.