When you first start selling, your account will be limited in terms of how many items you can list/sell in a month. Sometimes these limits are incredibly low, such as just ten items a month! Also with a new account, you run into issues with PayPal putting a hold on your funds so that it takes a long time to get the money from your sales, and this can really be an issue because you have to cover the funds for shipping out of your own pocket until your PayPal funds start clearing on the same day, after you've established your account after a duration of time.
There is a UK-based business called Power Seller Shop which has been set up with these very concerns in mind. They sell established eBay accounts so that sellers not only avoid the limits given to new sellers, but the established accounts also come with a solid feedback rating. Another challenge for new sellers is building up feedback; sometimes you just don't get sales starting out because nobody wants to buy from someone with zero feedback.
Power Seller Shop sells different "levels" of established accounts, from accounts geared more toward brand new, inexperienced sellers to accounts that have been established as "power seller" accounts for people who want to launch into eBay at a very high level. Basically, there are people who have established an eBay business and want to sell their business and move on, and Power Seller Shop helps connect people with those sellers.
In brick and mortar businesses, you see people sell their businesses and move on all the time, so why not do it with eBay, too? If you could buy an established business and save the time and effort of starting from zero, wouldn't you consider it? I think this is an intriguing idea to be sure.