eBay has moved away from being purely an auction site to become an alternative to Amazon for people seeking out new items. (80% of eBay sales now come from new goods). So many of the people visiting the site automatically click the 'New' filter when commencing their searches.
Changes to eBay's payments system for sellers, eliminating PayPal and insisting upon having sellers' bank details, haven't got down well with everyone. At the same time there has been a very big rise in the popularity of sites that don't charge sellers anything at all for advertising their items. For clothing, Vinted is probably the market leader, with Shpock being the most popular for other types of sales, but with Depop and others doing well too.
For finding local buyers for items, Facebook Marketplace is now incredibly popular, as neither the seller not the buyer have to pay any fees.
So, although eBay most definitely isn't in its death throws, it's now up against much tougher opposition than it was in years gone by.