it's not really about morality. When bitly decide the ad revenue and premium plans don't cover the hosting any more, massive chunks of web infrastructure will fail. When was the last time you followed a link to a running website and it failed? A few network issues here and there yes, but refresh and you're fine. When bitly bite the dust, that link is gone forever and you'll never know where it went. In thirty years I can look at a direct link and know where it goes, and if the endpoint is still live I can go there. Not so with bitly links (and don't even start on the smaller shorteners. They'll probably fold within the next 2 years)
I think the consequences are going to be more severe for dead links. Today I deal with permanently dead links pretty much every day. With the canonical URI, there is some hope there's a mirror in archive.org or the Google cache. If not, I can search for [parts of] the URI and hope someone mirrored the page, or has quotations from it. bit.ly URIs are a black hole.
At least on TinyUrl, you can preview links (prefix the links like: "preview.tinyurl..) But you are correct about sites going down. Biy.ly or TinyUrl goes down, so do the links.
