Good morning,
Imagine - Shimano execs are sitting in meeting back when Dura Ace was 7 speed and they decided to make the jump to 11 speed.
11 seems reasonable after all who could ever want more? 12/13 come on now you are just being ridiculous.
So 11 speed Dura Ace is made. Do they announce it well in advance or just spring it on the market?
By making such a leap Shimano have introduced a huge problem for the whole bike industry, just replaced 7 speed Dura Ace is obsolete, not just last year's model. So do bike makers offer some form of discounted upgrade for those who just bought it or say sorry, tough luck? Do they refit existing unsold 7 speed models that are in the supply chain with 11 speed?
Pre covid it was common to see 25%-30% discounts on last years model, but would this persuade many to buy 7 speed when 11 is now normal? More likely they would have be offering discounts to attract people who are not racers and had never considered Dura Ace but at 60% off the whole bike, why not?
The same issue applies to Ultegra/600 groupsets and bikes as many were bought by competitive riders for whom the cost saving/performance loss made 7 speed Ultegra a decent choice over 7 speed Dura Ace, but not a decent choice over 11 speed Dura Ace
Most users of of 105/Sora would be unaffected as Ultegra/Dura Ace was never considered anyway.
Then there may be limited supplies of 11 speed Dura Ace leading to articles in the press saying, team/rider claims they lost the race because the winner had 11 speed and we could only get 7 speed. This argument holds much less water when the difference is only one cog.
Shimano could pre announce the 11 speed group set which would mean that 7 speed customers would know that their new purchase is obsolete, some may buy after demanding big discounts but many would wait. This would of course cover not only the groupsets but complete bikes in various stages of the supply chain.
As of now Shimano now have a well balanced road range, each groupset offers "something" over the next step down but each new version of a groupset doesn't make much, most or all of the existing groupsets obsolete.
So I am suggesting that the one cog at a time is more about maintaining good relations with bike makers, retailers and customers than it is a technical thing.
Bye
Ian