AIBU or is this is really pointless thing for anyone in the chain to say? Does anyone want it to drag on endlessly? Also, isn't quick a bit unrealistic when mortgage providers, brokers, conveyancers and estate agents are 'unprecedentedly busy' (their words)?
It has been said by another party every time I've bought or sold and seems to raise unrealistic expectations that always fail to be realised and lead to frustration and grumps from the person who asked for 'quick' in the first place.
Lots of people don't always want to move as quickly as possible. For example, people who have school-age children often want to move in the summer holidays, first-time buyers on long tenancies want to wait until they're at the end of their tenancy, some people know they're being relocated with work up to a year in advance but obviously don't want to move before the change happens. You appear to think that just because you want to move as quickly as possible everyone else feels the same way.