Is there any way to turn allow offers as default setting? Shopify does not let me to use this function anymore.
I don't know much about eBay -Shopify integration I'm afraid - but if you want to allow offers on your Shopify store there are a few negotiation apps you can try - Nibble is possibly the most similar to the eBay experience because it allows your shoppers to have a chat to try and agree a deal.
Hey Rory - Glad you raised this! I'm actually a Shopify dev, and my team (all former McKinsey and Google alums) are building a product that may be helpful for this.
Would you be interested in connecting?