It is perfectly possible to sell products that you do not have in stock. Why shouldn't it be possible?
Why not keep stock?
1. Saves a lot of money and risk.
2. Allows quicker progress (no old stock to get rid off).
Most shops will try to keep their stock-levels as low as possible.
For a product like bicycles (fairly high levels of wear and tear) you would expect a shop to have stock of replacement parts for repairs and maintenance (tyres, tubes etc.) and for sales purposes you might expect / hope for the possibility of a test-ride, particulalry for high-end models. However: people have been giving bikes for birthday presents etc. without test-drives for a long time. As you attach more value to the bike the requirements will change (if you want to do a daily 20 mile commute you will be more keen on riding comfort, reliability, servicing arrangements etc. then when you buy a kid its first bike to see how they like it in a supermarket's offer).
Particularly eBikes will be failry high in risk to keep in stock (high cost per item (+insurance and write-off) , lose value quickly as new models are released, etc. etc.).
So that's why.
Would it be desireable for consumers to be able to enjoy the advantages of high stock-levels? Well it would be nice if we could just buy and not wait, do testdrives, had no waiting times for repairs etc. At the current sales volumes of eBikes these stock-levels are not sustainable, unfortunately.
just my 2c.
Isn't it just so frustrating when you find something you like, you put time into researching what you want to then discover the seller has no stock. And to be advised the stock will still be "months" away is just amazing.
If you have no stock, you can't sell it. Simples!