Personally I was a co-op rat around the Great Recession learning how to build bikes from parts, and in the process realizing that you can build a nice riding bike from 50-60 year old parts. You don't have to spend a fortune on Di2 and carbon.
Now these folks are in more prestigious positions and the industry is paying attention to the demographic. We get companies like Crust and Velo-Orange and Riv selling us bikes based on how we actually ride (or like to think we do).
I also race, but I race on a modest steel bike and only for the love of the sport, not because I'm a top tier competitive athlete.
There is no speed benefit for a non professional on a carbon frame, but wheels and positioning are a totally different story.
I ride titanium only these days because it looks good and its a tiny bit more soft than carbon, so for longer rides its more comfortable.
Bit I ride 40mm corima wheels or 60mm dt Swiss when I need to go fast in the bunch. And that makes the most difference along with my posture on the bike.
And if you lose 2 kg you can ride on a cheaper frame and get the same result due to your own weight.
Cycling for amateurs is more about looking good, egos, and spending money than it is to make the sacrifices around what it takes to go really really fast.
But ride your bike. It makes one happy.
Yes there is, I and many people have directly measured it.
LOL, no. I can jump on my aero road bike, do 300 watts and get an immediate .5-.8 MPH speed bump. Sure if you're a rec rider and you hit Z3 at 120 watts, then you will see no benefit, but there are plenty of non-pros who do.