Left to their own devices or on the front, the climbers will toodle along on the flats at a comfortable pace for themselves. You can't "make" someone pull for your benefit, as demonstrated in one pro race after another. The trick is to elevate the pace just enough that they're having to work some, but, not a lot to stay "attached" to the group. Just fast enough that the word "attached" is more descriptive than "sitting in". In my bunch, everyone seems pretty comfortable with a 36kph paceline. But, increase that to anything over 38kph and the "climbers" start to have to work, even when attached to my wheel. If I could sit on the front at that pace indefinately, you are correct, I could probably out climb them. But, I can't. The tactic requires at least two, preferably three cooperative riders. So, that you too get adequate recovery time. And deliver the "climbers" to the base of your next hill with at least a little wear in their legs and with a slightly elevated heart rate. It's just a tactic that keeps the climbers from dictating the pace of an entire ride by wasting everyone else on the climbs and then expecting them to be greatful for getting a "recovery" on the flats, just to repeat the cycle again. Keep the pace a little higher on the flats, and the pace on the climbs naturally comes down a little, keeping the bigger guys in the mix more and leveling the playing field.

Ain't it entertaining? How even a bunch of "never were's" out on a "casual" Saturday ride can start to play with each other as though it were a grand tour?

Even at our slow pace, there's definately a bit of competition with regard to who reaches the top of any climb first and in what order the rest follow.