Actual trail riders mostly do not do this. Source: worked at a bike store. People with a lot of money that treat their bike as something to optimize and not something to ride do this. I'm not saying its wrong, its just another way of being a bike enthusiast, but this type rarely overlaps with serious riders. Training improves performance, not $3000 wheels that shave off 50 grams.
At least in the pacific northwest, mounting biking isn't just about riding the bike any more than owning a motorcycle is just about riding a motorcycle. It's a culture or talking about and bragging about bike tech. Weight is bragging rights for mountain bikes as "aero" is for road bikes. Lots of people will pay to have the better toy. The running joke is that many bikes are worth more than the cars that bring them to the trailheads.
I think your confusing regular mountain biking with ebikes. The people bragging about bike tech will most likely be looking down at people that ride ebikes on the trail.
Agreed. For most people it would be more reasonable to lose the three-four kg in body fat and keep the aluminium frame rather than upgrading to carbon fibre.
Unless you have found a way to spend a few thousand dollars to make 3-4 kg of body fat magically disappear with no complications or effort, losing weight and spending more on a bike are not things you're choosing between.
Other than pros most of the people spending lots of money to shave weight would be better served losing weight from their belly over the bike, but that’s harder to solve with a credit card.
I don't think people with e-bikes even pedal into the orange zone. It's more of exercise theater, to borrow a term. HOwever, I do hope e-bikes start to overtake cars as modes of transportation in temperate climates.
