Hard to predict what brands will stick around, but the brands that survive will have the best business model, and not necessarily the best product.
What will surprise people the most, is that many brands that SEEM to have popularity now, are most likely NOT the ones that will survive. Precisely because their business models don't allow dealers to make enough to even live on, or are just poor, or they are naively going direct to market on-line.
These brands in no particular order that will most likely struggle:
Evelo
Pedego
Juiced
GoCycle
BigCat
BikTrix
BionX
Dillenger
E-Joe
E-Rad
Prodigy
eVox
Ez-Pedelar
Genze
Grace
Igo
IZip
IES
Jetson
Leed
Motiv
OHM
OptiBike
Populo
Prodecotech
Riide
Sondors
Stealth
SuperPedestrian
VoltBike
Wallerang
Van Moof
There's at least 50 more, than aren't worth even mentioning.
Survivors could be, IF they even decide to keep doing e-bikes:
Bulls
Specialized
Giant
Scott
Worksman
Stromer
Haibike
Schwinn
KTM
Focus
Emotion
Cube
Reise & Muller
Benelli
Yamaha
Trek (though the name may stay, they may dump ebikes if it doesn't go well)
Some names may survive and get bought out, if they have some sort of unique niche they've captured.
None of the above matters anyway, as I predict hundreds more new names will be forthcoming, until the market gets this right. Its WAY too early to speculate on any of this, but it might be interesting to look back in 5 years to see if any of this was right, or wrong.