I agree with Jasono. The word 'decent' is very subjective. Someone who wants a
£399 folding bike to nip down the ride to the shops once a day for his newspaper will probably find a lot of models out there which are very decent. 'Decent' to him means convenience, value for money and does its job. Someone else may have a budget restriction - eg 'My limit is £700'. A bike that gets them from A to B in reasonable comfort and with reasonable reliability for this sum will be, to them, a 'decent' bike.
If branded components are a minimum requirement for making a bike 'decent', then its unlikley you can get much below the £1K tag. For very expensive components this will of course edge up to £2K - but purchasers in this category would not consider anything less to be decent.
I have two stories to relate. Late last year we were invited to a meeting with our local council with the aim of supplying a number of e bikes for rent to companies in the area. Our recommended model was the
Sundowner - low maintenance, front wheel motor, Shimano Nexus gears etc. 'Shimano?' said a Dutch dealer who was also there. 'But they're cheap'. Clearly, ours, to him, was not a 'decent' bike, and his proposed Swiss model, at £2500, clearly was. The Council is still deciding.
A good customer of ours brought in a Ferrari bike last week for repair (damaged cables).Not an E bike, although it did have an electronic gear box and front fork with cable damage and missing connectors. It was indeed a very fine looking bike, weighed around 15 Kgs, with leather accessories and had cost its owner £5000.
To the purchaser, this had been a very decent bike. To us, trying in vain to get technical information from Ferrari (the Ferrari shop in London come up with no technical helplines or websites) with regard to pin-outs etc, it wasn't!