I have been dealing with bicycles and motorcycles and cars and trucks and computers for more than 50 years and one may sometimes get better performance by paying more that is not something that one should take for granted. A $1500 laptop is not going to be more reliable than a $500 laptop. A BMW is not more reliable than a Toyota or a Honda. The problem with lower end bikes is that the buyer needs to be relatively self sufficient. But to pay an additional $4,000 to get a Trek or Specialized e-bike is no guarantee of reliability and with a mid-drive motor the durability is going to be reduced and that is a trade-off from the design and current state of the technology.
The e-bike components are improving year to year so it seems foolish to spend $8,000 on 2019 technology going into the 2020 and 2021 bikes. It seems more prudent to buy something for the short term when it comes to e-bikes and even if one spends $1,000 on repairs and parts for it over the following 2-3 years the owner still comes out ahead. Lots of opinions but nothiing in terms of real world empiracal testing of the bike components or any information on MTBF for the hub or mid drive motors or the controllers or the battery packs. It is really a crap shoot at this point in time.