Rainboe
Easy are no different from any other low cost operator, if you book 3 months in advance you'll get a good rate, if you try and book the day before you'll pay the full rate.
In all sectors of industry it's supply and demand, if you have a product someone wants, you don't have to to offer discounts to sell it.
Personally, I very rarely use the extensive staff travel discounts I can get, largely because, (with few exceptions), they are all on a standby basis.
For a few £s less, I can get a confirmed seat with most low cost operators if I know where I want to go far enough in advance.
If it's short notice travel, I can fly nearly anywhere with BA on their World Traveller tickets, which cost a little bit more than standby tickets, but provide a confirmed seat and full service.
(Even it is in a camper van
)