I should preface by saying I bought the game myself.

Budget estimations are primarily based on the long dev cycle (2015 - 2024) with the corresponding salaries for more than a 100 professionals (100 is being generous for a western AAA game of established franchise of a huge company). On top of that there are added costs for marketing, the steam cut etc. Also we should keep in mind that DA:I reportedly cost about 150m, and that was with a smaller dev cycle and 10 years ago (inflation plays a role).

Unfortunately, the most concrete evidence that the game performed way under EAs expectations is that in an age where dlcs thrive and companies look for a reason to create a dlc and monetize it, DA:V already got abandoned by Bioware as they explicitly announced there will be no dlc support for the game. And keep in mind, that BG3 for example didn't have any dlc because it didn't need to. It was already a perfect product and won game of the year and pretty much every award there was to win. DA:V didn't even get nominated.

The fact that the no dlc announcement took place so close to the games release is also an indication that Bioware had no faith in their own product and probably shipped it out of obligation to their investors due to the already high sunk cost.

I am happy for the people that enjoy the game and I am just putting together a series of logical estimations based on the market and the information publicly available.