We still don't actually know how well DAI sold, for the record. EA has never released official numbers. A game that launches really well doesn't necessarily predict a game that remains strong; see also: DA2. I'm confident it's done decently, but doubtful it's done as terrifically as the PR-speak would have the average consumer believe.
Preemptively: VGChartz is never a reliable source of numbers.
I just don't think we've seen a lot of the kind of negativity we'd see on a tanking product. More to the point, it doesn't seem like - aside from DG moving to a new product - that there really have been radical changes on the DA franchise at the top (and certainly not e.g. scrubbing the whole game). When TOR struggled, heads rolled.
The trick in this type of business is to beat expectations. If DA:I did that, then, like a movie, it'll be considered a success regardless of its actual sales #.