That's the absolute least effective way of discouraging the practice. It's the strategy companies want you to take, but it influences companies the least. Collective action by consumers is a much better way of effecting change, including politically or legally, as they did here.

It definitely is anti-competitive to have none-removable batteries: it stops your old product from competing with your new product.

Finally, as a matter of fact, the battery in my mid 2015 iPod nano is literally soldered together, like you say, and that has stopped me from putting in a new one, like I did myself with an iPhone 3G.