WotC have taken different views over canonicity over time, since WotC isn't a single entity but many, of varied backgrounds, and the person making the decisions now isn't necessarily the same person as 15 years ago, let alone 24.
You can see that in 3E when they shrank Faerun in FR in size by 20% to create new maps, completely eliminating wide swathes of the continent, rendering some prior novels impossible to have happened and immediately nullifying products that came out just a year before (the FR Interactive Atlas). There was no in-universe explanation for this, it just happened. Whilst 2E assumed the existence of a canonical "D&D Multiverse" where all the official and homebrew settings coexisted (explored in the Spelljammer novels which started on Krynn, moved to Toril and then elsewhere, or Lord Soth being exiled from Krynn to Ravenloft), 3E abruptly separated each world into its own cosmology where none of them should ever meet again.
5E returned Faerun to its proper size and even gave a nod and wink to it in the text, and also restored the singular D&D Multiverse as a concept, meaning crossovers out of the whazoo are once again possible.
FR Wiki takes what I think is the only sensible view that all of the official products have happened and as long as they can coexist (which they can, mostly), there isn't a problem. WotC's canon policy seems to be arse-covering in case they mess something up big time in 5E versus earlier editions, but so far they haven't really done that, and have generally stuck to a very small part of the setting and been very reluctant to pin new information down so they don't have to worry about it.
Going back to DL, it'll be interesting to see what their view is on having retconned both DL and Greyhawk back to earlier points in time, whether the later events still happened/are going to happen, or they're just pretending those things never happened. Weis & Hickman's new novel trilogy seems to be at least teeing up the possibility of a timeline reset in the narrative back to the War of the Lance, suggesting the later events will be retconned out of having happened.
On a more subjective view, there seems to be at least some agreement that the quality of the new worldbuilding material coming out of WotC in the recent past has not been remotely a patch on that done in the past, particularly by those worlds' creators, so taking a minimalist view on creating new canon is probably for the best.