"Single point failures" like a puncture, a collapsed wheel a broken fork etc., indeed who designs these bikes with such failings, more who would buy them?
Perhaps because these issues come with the territory, we accept them and in some cases can live with them with very little effort, a packet of tube patches or even a spare tube, even as said a couple of chain coupling links.
Seems odd to dismiss all that crank drives can offer by singularly picking out that one particular issue, whilst living with all the other single point issues out there.
Do these people not travel in cars with just the one engine, one transmission system, just the one steering system, or fly in planes with just the mono wing?
Let me guess, you possibly own a mid motor bike? Is it a Bosch?
Failures that you pick out, except for the odd puncture, I have never had in
over 60 years of bike riding! I do not consider any to be SPOF problems.
So they really do not play a part in normal bike riding for me personally!! One can forget them completely.....
I have never had a collapsed wheel, who has? Some who drive their steeds very hard?
I have never even had a broken spoke, maybe because I adjust them myself several times a year....
I have never broken front forks either? Or had problems with the rear suspension on innumerable bikes...
But as we all, sorry, most of us know, the chain is literally the weak link (pun intended!) on any bike. It is stressed quite heavily on normal bikes, especially with a fit and muscular rider, and needs good maintenance and lubrication.
Now on mid motor e-bikes,not only does the chain have to stand the strain of possibly a strong rider, on a bike that is FAR heavier than the non electrical bike, putting far more strain on this single component, but now it has to pass ALL the power of the motor as well! Its no wonder for most of us this was a poor design.
On a mid motor, the human toque is added to the motor torque.
Now a few manufacturers apparently agree with us, and are starting to design mid motor bikes with other forms of transmission, other than a thin bike chain. So the "Single point of failure" has been recognised by a great many and written about many times, so good for them. But the prices they are looking for sometimes, make even Bosch bikes start to look cheap!
Then there is the cheaper end of the e-bike market, with front or rear hub motors, that do not drive the chain, only the rider does! But this must seem like a "holiday" for the chain, as the rider only needs to add some power when needed, a lot of his ride will be mostly e-power.
This results in far, far less wear and tear on the chain parts, a more relaxed rider knowing that the SPOF has been completely erased, as if by mischance the chain breaks, he simply removes it and rides home on electric power only! Hopefully not having just made a fully drained battery, because then he will either walk, or need some replacement bits and a few simple tools.
I can only speak for myself that I only ever walked with a flat tyre, and since I have puncture proof tyres and inner tubes, it has never happened again! I stopped carrying both tools and puncture outfits for that reason.
I forget exactly when I had to replace (at home and planned for) the chain and the rear cassette, but it must have been well over 20,000 KMs, possibly nearer 27,000 and it was done just once in the 8 years, of a bike that was in use every day, several times, except when snow or ice was on the ground!
Then I walked!
regards
Andy