I think it's not missing what you never had. At the turn of the last century, a troop of us army soldiers rode 50 pound steel unsuspended bikes considered pretty primitive today from south Dakota to St Louis- a thousand plus miles on unpaved roads or no roads. With a full pack. WE couldn't ride those bikes! Not to the coffee shop. Too spoiled.
There's a documentary about this on PBS American Experience, lookfor it, and it centers on the fact that they made the black soldiers do it, but this is also the story of the first hardcore cross country gonzo dirt tour. The safety bicycle was being tested to replace horses or marching, then the internal combustion engine came in so it never happened. At the same time, the wheel played a huge role in the womens suffrage movement- the bike helped us get the vote!
Anyway, other people ride tours on hybrids too. I know retired racers with SI joint problems who use high quality hybrids with Look pedals to go centuries. The issue is more about good equipment selection, good fitting, good fitness. If you're comfortable on your bike and riding these events in fine form, keep at it. When you find yourself leaning low over the bars too get more aero then it's time to look at drop bar bikes but as long as you are comfortable and having fun, keep having fun. Not every body can do the aero position for 100 miles, and bike people can get pretty equipment snooty. I do it myself. It's excitement over neat toys.
To Txchris's credit, a lot off shop staff WILL say anything stupid to get you to buy something. Be picky, ride only what you like and feel good about.

missliz