Do you mean bus industry deregulation or airline deregulation? I think the long-distance bus companies got hammered when it became really cheap to fly. The remaining really strong markets for bus travel is for really short trips, sold really cheap. They don't even need to bother with terminals, just a bus stop on the sidewalk. And they're doing good business, too. Why should they spend the money for frills their passengers aren't demanding?
The New York Terminal for Megabus.
The New York Terminal for FlixBus, right across the street from Moynihan Train Hall.
Actually, there are still long-haul customers and Greyhound's problem is that they have most of them. On a Denver<>Las Vegas trip a couple of years ago I met a passenger from Newark, NJ who was traveling with his wheelchair to Vegas. He was on the northernmost transcontinental Greyhound schedule (New York City > Denver > Las Vegas > Los Angeles.).
The station problem is that not everything can connect in time with everything. The curbside carriers -- a status to which GL aspires -- can't run a network unless they can sponge off of a public facility at connecting points. If it has limited hours of operation (see Knoxville story), then there still is a problem.
The station problem was going on since the 1970's. In the mid-1970's, as an economy measure, they began getting rid of the field representatives who worked to set up local agents. In that period, they got rid of at least the Oregon part of their Teletype network -- long before e-mail could substitute for it. Way back, we touched on the downward trajectory of the intercity bus industry as politely as we could in the 1975 Oregon Intercity Bus Study.
At the time, they were still tightly regulated. There were state and federal differences, but one of the reasons for the regulation in the first place was the terminal problem. It's not surprising that the Union Bus Depot in Portland, Oregon opened in 1937, when federal regulation was taking hold. Before that there were Knoxville-style fights all over the country.
The regulatory system began to break down before deregulation, thanks to the interstate highway system. The regulatory concept was used to cross-subsidize small town service with revenue from linking big cities. That revenue was cut into by the new ease of operation for irregular services, legal or illegal. It became easier for regulated independent charter companies to operate over a much larger range under their existing authority without needing relief drivers. The expanding services of truck stops made it easier for unregulated charters to eat into the business. It made it easier for lower income folks to drive a round-trip to drop someone off and then return deadheading to home.
All of that was going on without the help of discount airlines, which added to the problems. I also should mention package express, which bloomed dramatically with the end of railway mail service and the bankruptcy of Railway Express and then lost out to better service offered by FedEx and UPS. Deregulation in some cases just recognized what was going on. By the time we did the Oregon study we had concluded that it would be more honest to say that society needed to subsidize some defined essential services rather than expect cross-subsidization to survive. (I'm sorry that I did not save the information, but there was a British libertarian economist who supported the same idea.)
Regarding stations, the Knoxville and Meridian examples illustrate choices for municipalities. They can either punish the traveling public by not tackling the issues or they can try to take advantage of it to become a better city. Well, there's also Albany, NY - do studies and then wait.
In this 1977 photo at the Portland Union Bus Depot, the Special in the background is a solid package express trip.