Inexperienced,
A very thought provoking topic, and I suspect one that does not have a single 100% correct answer.
The underlying premises of your post is, respectfully, very sound - people have differing strengths and weaknesses, and ought to be able to ride to their strengths and exploit the weaknesses of those who they race against. The essence of racing.
“Taking your turn” would seem to be the antithesis of the individualistic approach, as “taking your turn” involves an element of collective effort for a common goal (less effort for more speed).
The custom of being required to “take your turn” probably has developed over time, but I guess it has its origins in fairness. Drafting confers a real advantage, and it might be said to be unfair for riders to draft behind other riders without bearing any, or less, of the burden involved with providing a draft.
The custom may also be derived from provide racers of more similar abilities and so closer races. I can see how that might happen, although in my experience those who wheel suck then sprint to fight their way up the grades do less well once up in a higher grade. Those who take far more than their fair share of turns, and still survive in the break or sprint to win, do better when they go a grade. There are exceptions bit for the most part the opportunistic wheel sucker does not do as well when they are up a grade.
Good point, with respect, about where the custom to take your turn ends. I think the answer is “it depends”. Think of these situations:
• The difference with pro riders is not so much that they are pros, but that they race in teams. Within a team there are the workers and there are the protected riders, so the workers take the turns while the stars stay fresh. The team takes its turn when other customs require (eg protecting the front running GC rider) or tactics require.
• Close to a finish, or a prime, the requirement to “take a turn” ends – when you get to that point then the collective benefit of drafting ends, and it comes down to individual finishing ability and tactics. Note I did not talk about sprinting ability and tactics, because the good time trialist might attack a fair way from the finish because he (or she) knows that the sprinters will not have the stamina to maintain a high pace and a sprint, just as a sprinter will probably find it better to keep the pace low until a short distance from the finish and use greater acceleration to win.
• An interesting issue is how the requirement to take a turn seems to vary depending on the work you have done. The more work you have dome the more people, including fence sitters, let you do what you want.
• “Taking your turn” is, from my observation, a custom that exists in all local grades, and wherever the custom exists there are those who push the bounds of that norm for their benefit by wheelsitting as much as they can. Listen to the A graders
**** and moan after a hard race with a cross-wind.
However, I think drafting does become more tactical as you move up the grades. In a B grade race in a strong cross-wind most riders will “ride up the gutter” to string people out and cause riders to get dropped, but it is rare to see in a C grade race in the same conditions (and then only when there are people who have raced from higher grades), and I can not recall it ever happening in D or E grade when I raced in those grades.