FWIW OpenBazaar has not dropped Bitcoin as a method of payment, just chosen to diversify payment options.

Using the blockchain for one-off payments between participants is never a viable solution. The establishment of lightning allows commits to be aligned with the long term relationship between two participants. Even after that relationship ends, a completely unrelated payment may be routed through your channel, earning you a micropayment. There was never a solution to that type of functionality with a 10 minute block creation schedule.

That went live on main chain two days ago.

https://www.youtube.com/watch?v=a73Gz3Tvx3k

Blockchains are successfully used for one-off payments, even Bitcoin used to be. Not anymore. And Lightning doesn't solve that problem. Thus other cryptocurrencies will thrive as methods of payment, whereas Bitcoin will remain a settlement layer for recurring payments at best.

Ah lightning network, the vaporware that is always just around the corner...