That's $300 for desktop and mobile together, for nearly the same features. Mobile is desktop with extra additions
Nobody is forcing you to buy it if you don't want to, and it's iOS and Android together so it works out to $100 each.
Given the amount of API changes and hoops Apple and Google make you jump through to be compliant for store release $100 per platform is pretty reasonable considering the continued work that is needed to keep the exports up to date and compliant.
Also the export licences are the least of your worries if you want to release on the stores.
You'll need a $99 dev licence from Apple (per year), $30 for a Google dev account (one time fee).
Then you'll need a Mac for Apple development, which I'm not sure of the current prices of but it's at least in the hundreds of dollars for the lowest viable Macbook which supports an OS and version of xCode Apple will accept.
Then on top of that you will ideally have a range of mobile devices including both phones and tablets (old and new) to test your game on before release to make sure it works properly and performs well on all device hardware and aspect ratios.
At that point the $100 for each mobile export isn't the main concern.