Understand that bike fitting is a very subjective process. There is no correct or optimal fit for anyone. Recommendations can be made, but like saddles you need to experiment, you need to feel it after 3+ hours. I've seen a lot of good fits, but a lot of bad fits. Many of the bad fits were done by a "reputable bike fitter".
Why would I pay money to get a bike fit, when there is no guarantee that I'll get a correct or optimal fit? If it's just experimentation, everyone can do that on their own, why then do we need bike fitters?
There is no such thing as "optimal fit". Its like fitting a suit. Everyone has their subjective opinion on how it should be "optimally" done. Whether that is a few mm higher saddle height or higher handlebar height, part of it is what you like and what works for you. You get a fit because it give you a better idea of what works for you and what does not (ie. more appropriate saddle height). I can promise you if you visit 10 bike fitters, each one will recommend you slightly different, but most will result in a fairly similar position.
As for the above poster that also quoted me, I'm seeing Trek, Specialized, Cervelo, Giant, Cannondale, Felt, Focus, Colnago, Pinarello, Kuota and until this last year BMC as well. In 95% of bike purchases through the multiple locations I work from, I do not need to replace anything on the bike. The most common adjustment beyond saddle height/fore/aft is increasing the handlebar height. Manufacturers are stocking their bikes with size appropriate parts that fit the vast majority of the population.