reckon would be rare to find a company that moved out of city/town centre for car parking. office space cost would be the major driver, transport links/access to clients second, available skills in area, then maybe car parking.
Cost of office space, yes, OK, some of that was a reason too, but not necessarily the main driver - recruitment and retention of staff was! Access for clients was fine - same as for staff (and generally there would be a few car parking spaces for pre-booked favoured clients). Available skills irrelevant - existing staff transferred to new location.
Staffing was definately an issue though - recruiting problems due to no staff car parking! That mattered to a lot of people with available skills!