genejockey 

A bike is a bike on a flat group ride where you're not pushing any limits. If all your brakes have to do is slow you down a little, or bring you gently to a stop occasionally, then even the old crappy, pre-dual pivot brakes are fine. If you're riding in the flats, a 53/39 and 12-23 are fine. If you're in a group, you can run 36 spoke wheels and exposed cables without a problem. It's when you go beyond those limits that the improvements in technology matter.

I bought my favorite bike in 1997. Ritchey Road Logic, 8 speed Dura Ace. I ran 23mm tires and a 12-23 cassette. That worked great!
Then I started to do more climbing and so I switched to a 12-25. That worked better!
After 10 years, I tried 25mm tires. That worked still better!
After 22 years, and buying two other bikes, I realized I was only riding it on flattish rides, even though every time I rode it, I thought, "Yeah, THAT'S why I keep this one!" So I got a set of 7800 brifters, a 7800 rear derailleur, and a 12-28 cassette. And I started riding it more frequently again because it worked even better.
Recently, I replaced the 12-28 with a 12-30, and tried 28 mm tires, and lower pressures. That worked even better!!

It was a good bike as originally spec'd. But now it's a better bike. For me, anyhow.