Bike fits can work, they can also be a disaster, it all depends on the fitter.
I bought a touring bike from a bike shop that had a fitter that is highly respected in the roadie world. Part of the deal was a complete fit - the bloke took over an hour and was dead serious about what he did. Most impressive.
It didn't work.
Why?
He set me up as a flexible, fit young man who wanted to go road racing.
Sadly, I was in my early fifties, flexible but lacking core strength, not overly fit and with no interest in playing boy racer at any level.
Okay, that's extreme but it's common among fitters - they assume too flamin' much. My hyper-fit, hyper-flexible teen-age son also had a fit by this bloke and it was darned near perfect (note the difference in physical descriptions?)
A good bike fit takes into account your body, your strength, your fitness, your attitude to riding and what it is you're trying to achieve. NOTHING on the internet does that. NO fitter that measures things and drops plumb-bobs is doing that. Fitting can only be done by observation and dynamically and a true fitter understands that. The various mechanical methods can give a good starting point but nearly everyone will move from that ... unless they believe roadie lore which is why you see so many uncomfortable riders on the road.