A frustrating as Netflix cancelling their deal with Disney was, the advent of Disney+ really made it inevitable. It made Disney a direct competitor, so it would've been rather counter productive for Netflix to keep making shows all but advertising the competition.
Even so, the fact the streaming giant included a clause in the contract stating that Marvel wouldn't be allowed to use any characters that appeared in the Marvel Netflix shows for however long after each individual show ends just added salt in the wound.
But now, two years after the fact, that timer is just about up, meaning that we might just see projects featuring the MCU's darker and grittier residents be put into the works by the end of the year if all goes well (which it probably won't, but let a man dream).
Now, the idea of these more adult oriented heroes getting moved to the more family friendly streaming site sounds messy at best, but that needn't be the case. There are key areas to improve, but there's also a lot that Disney+ needs to do in order to distinguish their interpretations of The Defenders from their Netflix counterparts (if they eventually do see the light of day).