My brother goes to school in Pittsburgh and has taken the buses back east, and you're full of shit. First of all, Bolt doesn't even go from Pittsburgh to anywhere. And Megabus most certainly isn't nonstop to Philadelphia, it's got a stop in Harrisburg. It is indeed cheaper and has more options (3 vs 1) to take the bus, but Amtrak is almost always on time or early (last time about half an hour) and Megabus is in his experience laughably late. He's taken Megabus a few times to Philadelphia en route to our grandmother (in a suburb) and the time/price difference would be about 40m/$20, plus the SEPTA time back to where he wants to be (40 mins and whatever the wait is) except that there's a closer stop (Paoli) on Amtrak to his destination that means it's about an hour faster to take the train.
To NYC, which he's done more frequently, the time is even better, since he lives in northeast NJ and the train stops at Newark (9hr) and even if Megabus is on time to NYC it still takes about 30-45 minutes back to the house, so the time works about the same, with a lot less comfort. And that's assuming the bus keeps to their schedule.
First time he took Megabus (to NYC, not Philly), the driver was new and went the wrong way (west) out of Pittsburgh despite the passengers telling him he was going the wrong way. Eventually he was convinced to start following somebody's phone, at which point he bottomed out the bus trying to make a U-turn and ended up about 6 hours late because the bus was ruined and they had to wait for another one to transfer everybody on to, and then make it back an hour towards Pittsburgh to even get started. The next time, he was 4 hours late due to traffic and leaving 45 minutes late from the stop at State College, so instead of getting in at 9PM he got in at 1AM (to Midtown Manhattan!), and I had to drive in to pick him up from a street corner. The few other times he tried, it was miserable - either the wifi or power didn't work or the bathroom was out of order (so they had to keep stopping every hour) or some other incompetent problem, and every time they were just plain late by at least 2 hours. He's taken Megabus 6 times, and the service was so bad that 5 of those times he's gotten a refund. Which I suppose helps the price argument, but it seems like a pretty shitty way to save a few bucks.
Due to Megabus' demonstrated and utter incompetence, he looked into taking Greyhound instead, which should be more professional and does stop in Newark, but is barely any cheaper ($10 or so) and in fact slower - even as scheduled, let alone traffic, since it makes 3 other stops.
So despite Amtrak's suckitude (which I don't dispute) west of Harrisburg, mostly due to having to run over Norfolk Southern trackage past Harrisburg (and so limited to diesels and about 40mph), it still is a more pleasant and easier way to travel. He has plenty of room, usually a seat next to him to take a nap (comfortably), hot meals, etc. And Amtrak's working with NS on upgrading the Harrisburg-Pittsburgh route.
Sure you can do better by driving (about 6 hours to our house), but we're talking about public transit here. He doesn't have a car, and somebody driving out to get him doubles the time and cost overall.