I still think in the 'Worlds' marketing has a large effect, they get paid/sponsored to race. Said company needs a market and different product to flog you so will get the racer to ride where that different product is. They may be athletes, but they are paid to do a job.
I don't blame them, people will buy to try.
Except if it was a poor product, it would get found out. It wouldn't be endorsed by 'said' athletes as it may have **for example** impacted negatively on their results.
It also wouldn't be having such a dramatic impact on the sale of 26" wheeled bikes. If it wasn't a better product (for most)....Demand must be there for 29ers, as bike companies wouldn't produce 29ers on a whim, or a hunch.
I'm sure people felt the same way when 26" Wheelers entered the fray, particularly when BMX bikes where seen as 'it'.
It's acceptance of change people struggle with, for me I'm all for it. Look at Fat Bikes? WOW, they throw a whole new cycling experience into the mix, all good in my opinion.
Salsa Selma Naked Ti 29er
OS Blackbuck 29er
Van Nicholas Ventus Ti