It's definitely a factor, but not really. It's simply the fact that usage has always been really small, and people are simply just using the likes of eBay instead. Truth be told, bitcoin and cryptocurrencies are mostly held as investments today, rather than for payments.
Convenience goes above all else. As long as people are able to buy/sell items without hassles, nothing else matters. Decentralization is only a subject of interest to those who're concerned about government censorship/suppression. In countries where freedom is limited (usually in authoritarian countries), decentralized alternatives to eBay and Amazon does wonders.
It was surprising for me to read that OpenBazaar closed its servers 3 years ago. Wasn't it based on P2P tech? If not, then OpenBazaar isn't as decentralized as I've once thought it would be. With investors shifting their focus away from utilitarian projects, it's hard to imagine decentralized marketplaces will take off anytime soon. At least, the idea is there. The future can't be predicted, so lets hope for the best.
