Worth bearing in mind Bosch has made, literally, millions of motors.
That is a massive number for a specialist bicycle component, and will inevitably impact on the number of reported faults.
What none of us know is what percentage of a given maker's kit goes wrong.
I rate the Bosch stuff as pretty good, although I suspect their failure is little better or worse than other motors.
They are the Apple of ebiking, so the batteries are all but impossible to recell.
Limited spares are available to the public, although Bosch do promise to support their products for at least seven years after they fall out of the original equipment catalogues.
This means a replacement battery is still available, at a cost, in contrast to some of the 'unbranded' Chinese stuff where spares cannot be found even a couple of years after manufacture.
When I bought my first Bosch ebike - a Rose imported from Germany in 2010 - service in the UK was all but non-existent.
Things have improved now to the extent where service is available through UK dealers.
I've obtained two spares, a thumb control and a display, fairly easily.
Limited repairs can be carried out on the motors - a standard sized bearing is a fairly common failure - and complete exchange motors are available.
These are not cheap, about £700, but no crank drive motors are.
From all the statistics I've seen Bosch is a niche player in the UK in units sold and this isn't surprising as Bosch based ebikes tend to be many thousands of pounds but the average price of a bike sold in the UK including ebikes is only about £300 or thereabouts. Also
Halfords have 25% of the market by value and about 40% of the market by volume. I.e. 4 out of every 10 bikes sold are from Halfords in the UK. Then you factor in
ebay, Argos, Amazon etc there isn't actually a huge amount of volume left for independent bike shops and direct sellers although value of course is different as such bikes are hugely expensive. It's important to understand real world perspective. If you watch GCN and many other youtube channels you could end up thinking the majority of the bikes sold are from big international brands but that isn't the reality they are promoting relatively low volume high margin products.
Lets also not forget Bosch batteries are full of cells made in Asia and many of the PCBs and manufactured parts are from Asia too. Bafang claim to be a OEM supplier to European brand motors for some parts.
I worked in the power tool industry and saw certification for tools we imported that also covered other brands like Bosch. They were buying the same Chinese product as us but their marketing spiel had lots of references to quality German engineering etc. When I had a conversation at a show with a Dewalt representative he said its not about making a quality tool its about being perceived as making a quality tool. The two things are very different. That's not to say Dewalt aren't quality tools but they cannot rely on people's experiences of those products they have to market the tools in a way that makes them believe they are in comparison to their competition.
My understanding is ebike Bosch motors have a very high failure rate despite their high cost although in fairness I think the majority of their sales are in the e-mountain bike sector so they get a tougher life in some ways although it has been pointed out to me such bikes often have very low mileage and still fail as many owners only use them once a week or less sometimes where as commuting ebikes can be used pretty much everyday for 10s of miles.
I have to admit I think of Bosch motors as junk and wouldn't touch one with a barge pole but I think part of that is probably my resentment in the way they control spares and limit 3rd party support. I just don't like the company at all. I'm a bit of a Shimano fanboy but when it comes to ebike motors it has to be Bafang really.
One thing that needs correcting is your point about Chinese ebikes having a lack of support. They are very generic and you can use pretty much any motor, controller or battery you want if you wire it correctly. It's extremely open. You can often mix parts from different manufacturers. I've seen people bring old Chinese ebikes back to life for relatively little money. I've seen them take apart batteries and just replace the faulty cells. They are very modular. It's a bit like having a house where you can either use whatever products you want in the home for electrical wiring or you have to buy it all from one supplier only. Also when it comes to hub based ebikes if you wanted you can typically just strip out the ebike parts and return it to a normal bike. It's a far more environmentally friendly approach. You just don't get that with Bosch based ebikes often they are uneconomic to repair and you can only pull off a few components to re-use like the wheels.
I just think an open system is better. I resent any controlled eco-system for any product be it Bosch, Apple or whatever brand.
Also lets not forget this country has huge debts and a large trade deficit, its not exactly a bad idea to be conservative with our spending on imported products. We left the EU with about £1.7 trillion of debt with a large trading deficit. We have enough debt to probably last 40-50 years and we haven't even started to pay it off yet we are still borrowing because of the pandemic. Running a trade deficit does huge damage to our economy as can be seen from the statistics at the office of national statistics. Also if you look at our NIIP rating (net international investment position) we have negative assets. We keep swinging between two useless political parties and ultimately sorting out our economy to a degree is down to the purchases we make. I would suggest a lower cost, more reliable if basic ebike which is much more environmentally friendly and economy friendly is the right choice.