If Jon Snow can remain at Channel 4 News, Piers should be fine.
I'm baffled as to why they're not making an effort to an equivalent partnership for the non-Piers days. It reverts back to GMTV 2009 when he isn't there.
ITV feel viewers have enough to stomach from Mondays to Wednesdays, that for the remaining two days they need to recover before he returns on Monday. Also, if you hate Piers, then having Thursdays and Fridays Piers free helps. It wouldn't help if they had another ego maniac at the helm on Thursdays and Fridays.
That sounds like your personal opinion rather than fact. He may have negotiated a three day week as part of his contract rather than a commercial decision to not work Thursday and Friday.
Of course it is my personal opinion. I have opinions like everyone else, and I do not have access to the mind of Piers Morgan or the GMB/ITV team. It was just an opinion.
I have previously stated on here that Piers does have a fantastic contract with ITV, and indeed it looks like GMB/ITV are happy to have him on the air for three days a week, for probably 40 weeks of the year.
The question posed was why doesn't ITV have another partnership like Piers does with Susanna - my opinion was that I felt ITV were happy to have a sparky partnership on those three days, and did not want a similar form for the rest of the week.