> Recumbent is horrible to ride in traffic (you are below the height of most traffic)
Depends on the recumbent. Mine (an Azub Six) isn't - I commute through London on it every day. And cities are (slowly) getting better at keeping traffic out of the way.
> and the handling is atrocious.
How so? You have to take a different line through corners, but you turn later (front wheel is further back) so it's if anything easier to go through the kind of right-angle turns that are expected in cities.
> Yes they are maybe more efficient but they are not pleasant to ride.
That's the opposite of my experience - upright bikes put so much weight on the wrists and, uh, taint, that they simply can't be pleasant for any length of time (particularly for those of us of an, ah, less athletic physique). A certain proportion of the population is able to sit comfortably on a traditional bike saddle, but many people aren't. As scooters and e-bikes open up more of an on-ramp into cycling for a wider demographic, I'd expect more and more people to find that saddles aren't working for them.
> Shimano's hub gears need regular maintenance where traditional derailleur setup will go on for thousands of miles with only basic maintenance. Maintenance on a derailleur system is typically cleaning (fairy liquid is fine) and using cheap lubrication that can be bought for a few pounds/dollars will suffice in most cases.
Ordinary consumers aren't up to even basic maintenance - cars went through the very same progression, in the '50s or '60s it was normal for a car to require basic maintenance by its owner. Low-maintenance hub gears will continue to get cheaper (an expensive model like the Rohloff already goes for thousands of kms without maintenance) and commuter bikes are increasingly switching. I'm sure that racing bikes for enthusiasts will use derailleurs for many years to come, but for commuters who just want to get to work the hub gears are already taking over.