The county officials in the larger populated counties are almost all dems. They are not going to try to suppress their own votes. Money is the biggest driver of long lines. Machines, poll workers and polling places all cost money. Budgets are tight.
There are always long lines in big counties. Then where there are larger than normal turnouts, the lines are even longer.
and of course thousands of mail-ins are sitting in opa-laka, never delivered.