The thing to remember is that the CRs are never really gone, they're just silently inserted for you by the tty.
Dealing with raw vs cooked (where LF is automatically translated to CRLF) ttys in UNIX is also a giant pain when you have to do it, so in a way it's not surprising that they decided to leave that out. The original DOS kernel was very minimal compared to UNIX even of the same era. Of course, it turns out that having to write CRLF into files is also a pain - Windows has binary and text mode files instead of raw and cooked mode ttys - and one that you encounter much more often.
Dealing with raw vs cooked (where LF is automatically translated to CRLF) ttys in UNIX is also a giant pain when you have to do it, so in a way it's not surprising that they decided to leave that out. The original DOS kernel was very minimal compared to UNIX even of the same era. Of course, it turns out that having to write CRLF into files is also a pain - Windows has binary and text mode files instead of raw and cooked mode ttys - and one that you encounter much more often.