Marvel has a pedigree of success that makes it easy for them to use any character and see amazing results.
Are you going to say captain marvel is more popular than WW because her movie made a billion and windy couldn't?
No it's because the dceu is still new and hasn't gained the general public's trust and recognition like the much has.
That's why it's so easy for Disney to just throw out a blade movie or an externals movie.
If WB did the same thing it would have to be smaller budget films like shazam and joker