I think the fact that City only approached at the end of the window due to the Sane injury and the Sanchez deal not happening could have a major impact on thisNot really, the context is very relevant.
Mahrez has advisers (agents, lawyers) who will have told him that a "promise" that you can leave next season is only as good as the word of the person giving it.
If he didn't negotiate a release clause in his new contract and Leicester subsequently didn't think Man City were meeting their valuation and decided not to sell him, then that's own Mahrez's problem for not getting it in the contract in the first place.
Any promise Leicester made will be subject to them getting value for the player.
Leicester probably see EL as realistic and without Mahrez or a suitable replacement this becomes harder to achieve.
I feel he will go in the summer if a suitable bid comes in
I doubt City will pay 66/75 m for a reserve left winger