eBay doesn't sell goods, deliver goods, etc. eBay is a third party marketplace. While Amazon has inventory, warehouses and actually ships goods, eBay is only a website that facilitates third party transactions. Much as Paypal is only a payment intermediary. It's like comparing apples and oranges.
Over the last 10 years, Amazon's model has remained relatively unchanged as has their catalog and website. On the other hand, eBay can't figure out what they want to be. Constant change and disruptive innovation have alienated long time users. Ebay's love affair with big box discounters selling refurbished items and cheap Chinese penny sellers hawking knock-offs has made them the equivalent of a dollar store, while Amazon attracts more affluent shoppers who will spend more for quality items.
Totally Agree, Bottom line should be metric here, not Rev's as neither is a hyper-growth start-up striving for market share anymore...Those Days Long Ago. Presume internet tax implications same for both as well, & if AMZN actually starts to increase margins AND stops eating S&H --- the valuation spread between the two will increase.