eBay has been censoring email addresses in eBay messages for a while now to prevent people from circumventing final value fees with direct payments/purchases, but I just sent a message that did not contain an email address and got an error I sadly forgot to copy-paste which was along the lines of "it appears you are trying to complete a transaction outside of eBay and this message has been deleted." A red flag may have been raised by the presence of "Paypal invoice" because when I reworded to "direct payment" (after starting my message from scratch ) it appeared to send successfully.
I continually get the feeling eBay is willfully turning into Amazon, what with their increasing censorship of communications and enforcement of exorbitant international shipment policies and fees (34% duties to Canada through the Global Shipping Program, which many sellers cannot [or refuse to] opt out of, and which made my Canada Post delivery guy shake his head in disgust to hear about the last time he charged me the actual 13% government duty rate on a package) -- and I say this specifically thinking of Amazon's horrible employment policies for its millions of warehouse droneslabourers valued employees and the "paramilitary group" they employ for discipline security.
Its ok though, eventually someone will open a new auction site.
That said, that's all the more reason why Superego is correct in that nobody will be able to take over for Amazon. The scale of their operations combined with their excellent customer service, product offerings, and order turnaround time would be pretty much an insurmountable barrier to entry for all with the exception of Walmart.