I would say that it's very likely, the energy when all 5 got together just wasn't great overall and You can see that when they had the HOF induction with Steve there.
I'm sure Peter didn't want to commit to anything more of a one off Record it and be done.
Phil only wanted as I said before to do limited shows and both financially would not work nor would there combined schedules allow for anything lengthy.
As I said before, if Peter really wanted to do the Lamb reunion, they still could, but Nic would have to replace Phil.
I suspect, it's all down to Peter as per usual.