echo has long been unreliable. Even the built-in echo in the shells were unreliable in SunOS, because the shell would look at the binaries in your PATH and try to figure out whether to emulate the BSD vs SysV (IIRC) version of echo and then change what echo would do. So much for writing a single script (with echo) that would work for all your users on the same host.

This is why you'll see code like this: echo 'prompt: ' | tr -d '\012'

No other simple mechanism was portable at the time. Seriously portability-minded coders still use that line, because although the issue is finally dead in linux+bash (i.e. /bin/echo is enough like bash's builtin) - it's likely still broken in other Unixen out there.