You seem to interpret "progress" as "lower prices" :-)

I see how it can look like that. But no, they are two related but seperate effects of a healthily competitive market.

...a potential monopoly is the carrot that drives a lot of innovation

That is a statement that I can agree with. (And I wouldn't count a severely dominant player as a monopoly; a dominant player can drive a lot of progress as the smaller fish frantically try to find a way to one-up it and pull in customers)