First, isn't there an oversized fee for bicycles? It's easy enough to disassemble one and place it in a box like you would on Amtrak.
Amtrak bike boxes are significant larger (~10 inches taller, ~10 inches longer and a couple inches wider) than a standard bike box, like the one you get from a bike store or as specced by Greyhound (and airlines and UPS/Fedex). A standard box takes a lot more disassembly, and you have to be careful about padding it, because the tolerances are smaller. Last time I did it, it took me a couple of hours to get it right. And you need to get it right because if it comes out mangled on the other end you're screwed.
Even then there's no guarantee. Last year, I used cardboard bike boxes in Europe (on planes, you can just roll aboard on trains and ferries there). On a flight to Oslo, the box burst open and everything was delivered to me in a pile. It was Norway, so everything was there and the pile was neatly and carefully arranged. I was lucky, but luck is a bad basis for planning.
It's annoying to pack a bike into an Amtrak box, enough to discourage casual trips. It's also risky – you don't know pain unless you've seen your bike box sitting on a luggage cart under a ton of suitcases. That's why the roll up policy was welcome, even if poorly conceived and implemented. But it's a total pain and even riskier to pack a bike into a standard cardboard bike box. If you only do it occasionally (like me -- I usually use a hard case that's designed for airline travel) it's a major project.
To say it's "easy enough" means one of two things: either it's something you do all the time (like, you work in a bike shop) or you've never done it at all.
