According to Valve:

Over time, the battle pass grew into a massive operation that sucked up nearly all the time, ideas, and resources of staff working on the game. In the early days of Dota 2, content updates were more varied and frequent. But over time the battle pass began to consume every idea or feature, leading to a situation where for most of the year Dota 2 had little to no new content until the next big battle pass update.

and

While work is still in progress on future updates, the first of these has shipped: ‘New Frontiers’ and patch 7.33 couldn’t have shipped as they did if we were focusing all our efforts on producing Battle Pass content. The community response to ‘New Frontiers’ has helped us build confidence that working less on cosmetic content for the Battle Pass and more on a variety of exciting updates is the right long-term path for Dota as both a game and a community

Pretty wild, as this seems to describe the issue with most live service games and high end titles in general.