If your product has changed hands several times like Instapaper has, it's probably not particularly sustainable. Or at least nothing that any large company is interest in sustaining.
Luckily my "use" of Instapaper has dwindled. I still frequently send things there. But it's more or less
/dev/null for me. I rarely read what I send there. I've always wanted a similar product that intentionally limited my queue to a smallish number. Force me to choose what I'm really interested in.