Mining isn't the only issue although it's the one that gets all the attention it seems. From what I've heard RAM prices are high and this is a large contributing factor to the price rises - Gamers Nexus[1] on YouTube mentioned that the _bill of materials cost_ for building a graphics card had gone up by something like $20-$30 because of RAM and board partners are actually having to raise their official MSRP.

[1] https://www.youtube.com/watch?v=neNHVosINro