At this point in time this is flawed reasoning.
Most bikes are still doubles so you will need to buy extra to convert.
Same goes for groupsets.
Building a grouset from components would be even more expensive too.
As for performance.
- Less gears.
- More cross chaining.
- More riding at the small end of the cluster. Bigger jumps in ratios. More chain tension.

Yes I can see the application for one dimensional type events, eg, hill climbs, flat time trials, crits.
For road riding/racing on hilly or even rolling terrain it has to be a step backwards.
Adding simplicity, maybe, but the front mech and shifter is relatively simple.
What about the complexity of internal cables, Di2, disc brakes. People will have all of those and then say they are trying to simplify with a 1x drive train!
But just because it isn't better, it can still be the future. Like disc brakes.