This doesn't make much sense. Discounted first/business class fares are usually significantly less expensive than full Y fares. Unless they're really focusing this on government Y fares which are probably much much lower. Frankly there's rarely a reason to need to buy a full Y domestically, but on the other hand, often that's the only one-way fare available for overseas flights, and is usually more than discounted J.

Selfishly, I'm glad nothing is changing with the discounted "I" business class fares, there is an argument those should be less (though to be fair, not all I fares are actually so cheap).