Apple and Samsung spend millions of dollars marketing their phones. The money is not just the visable TV and internet adds. They also spend millions in MDF, every display poster you see at Best Buy, your local carrier store is paid for with MDF funds. Meaning funds from the manufacturer matched with funds from the retailer.
I just spent two weeks in Europe and every wireless store I passed had Note 8 banners and displays. I have been back a little over a week I would guess now many also have iPhone 8 banners. I can pretty much guarantee almost all the sales people in these stores know Samsung reps. They have received training and swag to get them to like Samsung. The most important aspect is the training, no salesperson wants to sale something they don't know.
You can repeat all you want that it is their job to learn does not matter won't happen. LG has the responsibility to train, empower and build a pipeline of sales prospects to walk in the stores asking for LG. How responsive is LG, they leave V10 displays up in Best Buy over a year after the V20 is announced. Best Buy does not care LG is paying for that space. What message do you think this sends to the stores mobile sales team.