The majority of quality ready made eBikes and Pedelecs do appear to be very expensive, and the four figure price tags must exclude a very large proportion of their potential market.That limited market must make dealer costs and margins higher proportionally.
For the DIY'er it is quite practical to build a high spec bike from a much more competitively priced high quality conventional bike and selective high spec electric components, mostly from China.
My own converted ebikes include a lightweight step through full suspension German Alubike, a secondhand German Hase recumbent trike, a £600 Giant trek full suspension bike, and a Dahon folder which each cost well under a thousand all-in, and have high spec original components, such as hydraulic brakes, sealed bearings and good quality frames and wheels.
They all have sine-wave controllers and sophisticated LCD head units plus watt meters as accurate "fuel gauges".
As the majority of cyclists these days seem to have less DIY cycle building and maintenance skills, many kits get thrown together with ugly tangles of cabling and poorly wired connections, so they often give kits a bad name and poor reliability.
One only has to look through this forum to see a great many superbly finished DIY ebike projects which are at least as good as the highest priced ready-made "Ferraris" of our ebbike world, and cost a fraction of them.