Don't feel badly - I've even got at least two service provider networking experts caught in the same trap.
Bandwidth does not equal speed all things being equal. Speed=Latency, Bandwidth=Throughput - consider this analogy, you have a roadster and a sedan. Both can move from 0-60 at the same speed - say 4 seconds (speed) but the sedan can carry 5 people (throughput).
The intersection of these can be noticeable for the following reasons:
1. there are a number of people in your house using high-throughput applications (video) - then more broadband throughput makes sense
2. Moving to a higher bandwidth network segment might optimize the networking and avoid congestion from older systems (MIGHT)
Those techies getting caught in this common mental lapse just eat some humble pie and share the word. If you want a faster Internet - you need a more direct connection and that's the only way to have one that is "faster" though moving to better DNS can help a bit - like OpenDNS is now the fastest