You might be right, but I think you're showing a massive lack of understanding of basic business decision making. The vast majority of the costs associated with putting in a planning application have already been incurred, so they might as well finish the first part of the job and put the application in.
By the time permission is granted, the situation on Brexit ( which may influence the financing ) should me much clearer. In the unlikely event that the finances aren't working at that time, then they can mothball the project, knowing PP is sorted.
You’re correct, once planning permission is in, much of the planning, work and finance has been completed, but the clock also starts ticking at that point too.
By law, there is a finite period (I believe, 3 years) where by, if circumstances changed and the club weren’t able to commence work for whatever reason, they would be forced to make a new application and double up on any associated costs.
Mothballing the project (or appearing to do so) once planning permission for something like this is granted, is an unlikely option - one that would cause a great deal of unneccessary concern and publicity.
It’s much wiser to hang on a few months, ensure the safety of the club on the pitch, assess the economic environment after the political climate has settled and make some firm decisions at that point.
That’s me with my naturally risk-averse hat on as a business owner.