Why does it take companies/banks 2 to 3 pay periods to get direct deposit set up for an employee? Why so long?

Tavy

Takes a week or so in the U.K. it's not difficult.

Trivial One

It should rarely take more than two pay periods. It takes two because your employer doesn't trust that you're capable of correctly writing down your bank account number and routing number. So, they test what you give them the first pay period to be sure the numbers you gave them track to an actual account. If so, the direct deposit goes through on the following pay period. It takes only minutes to do the actual set up.