I think it depends on the terrain. Motor difference and rider weight make a big difference where it's just uber steep, but when it is slightly less steep but more technical (rock steps and tight technical switchbacks), there is more emphasis on rider technical skill and line choice than pure...
How much of that is to do with the fact that all the big teams are running Bosch? There weren't many riders riding other motors. That could be because the big teams know which is the best motor to use or it could be because manufacturers with other motors didn't put a big team forward.
Also...
Riding conditions/terrain are going to make a big difference on how much you spend and what you have to replace. Living in dry/rocky mountains we replace brake pads and tyres A LOT (it also dictates which tyres and brakes pads we use), but we rarely change a chain/cassette (Normally we do 4000+...
Going out with non ebike friends is always good for a sociable ride, but a compromise for both parties (though this does depend on where you ride) - they get knackered thinking they need to try and keep up and we do fewer trails than we normally would/and ride up the road instead of the off road...
The technicality is required to limit the effect of motor/power/rider weight differences. Technical climbs are going to be more about climbing skill (obvs some bike/motor differences too). Whereas a less technical climb will just be won by the lightest person with the most torque.
Where you ride and who you ride with will make the biggest difference to the decision on whether to keep a non-e bike or not. For me, living in the mountains, with regular 1000m climbs, no uplifts and everybody else riding e bikes ( it is very rare to see non-e bike here), I couldnt see a reason...