Do bus terminals need to be at the train station?

The Adirondack Trailways map suggests that White Plains is between terminal locations in Nanuet and New Rochelle, then on to Queens Village with connecting service in New Rochelle to New York City, "Port Authority Bus Terminal 8th Ave. between
40th & 41st Street":

http://trailwaysny.com/index.php/route-map/

The direct route to New York City would be Newburgh to Ridgewood to New York City, completely bypassing White Plains.

So why does Adirondack Trailways need to go to the White Plains train station at all, much less drive down residential Barker Avenue rather than non-residential Hamilton Avenue? Wouldn't it be more efficient for it to have its White Plains location along 287? I'm guessing that people who get the Adirondack Trailways bus at the White Plains train station are being driven there, probably by parents, in cars. Those passengers could just as easily be dropped off on 287.

Similar questions should be asked about other bus companies. It seems intuitive that bus terminals should be located at a major train station but has that been reviewed in recent decades?

Such a review should include the Westchester County Bee Line bus system, which has its terminal on street level of that private parking garage in a desolate, wind swept area that Common Council members and Transcenter task force members would avoid. Who actually transfers between the Bee Line and Metro North? Task force members should know all this before making plans.