Their accents are different. Bob has a Midwest touch to his speech, as is standard for Illinois kids like him, Steve speaks classic Western New England, typical of his Massachusetts upbringing, which is almost exactly the same as American Standard.
But these two came up in the New York comedy world around the same time. They weren't close but had many mutual colleagues. It might be more about a similar performance style than a regional accent you're noticing.
The Western New England accent is very different from your classic Foggettaboudit east coast accent. Unless you're an academic linguistics researchers, it's basically the same as American standard. He was luckily born into his accent.
How West is Western New England? He was born and raised just outside of Boston. That's usually a pretty distinct accent, and not a foggetabouit accent. I see he went to school in Ohio. I think it's more likely he lost it there, but I'm just a random guy. I just throw theories out.
Yeah, I can understand the relation you're making there. They both have that upward inflection. Higher pitch. I don't know if their accents would be considered the same because of these qualities though.