I have thought a bit about the chances of Crash getting in Smash.
I will try to make a summary of the things that could help Crash’s chances:
-The relationship between Nintendo and Activision: this started getting notorious around 2014, with the Skylanders collaboration that featured DK and Bowser. These two returned in Imaginators, revealed on 2016 and probably developed since 2015. Activision has also supported the Switch with many ports, and even a Switch bundle themed about Diablo. This relationship could make the deal to have him in Smash more likely, and another point could strenght this (more later).
-The economical benefits that he can bring: Ever since the N Sane Trilogy released, Crash has become a money making machine for Activision, notorious on the UK, and even selling well in Japan. The merchandising has also given a lot of money to the company, and an amiibo could also sell even more.
-Crash and Japan: surprisingly enough, Crash has an huge impact in Japan. Before Spider-Man PS4 released there, the best selling western game there was Crash Bandicoot Warped for PS1, that being between the 90s and the current year. Crash is also popular among japanese Smash fans on the DLC speculation at the moment, alongside Banjo, Geno and Sora. We can say for sure that Japan will benefit Crash.
-The requirements of the DLC packs: Crash can easily fill the requirements that each DLC pack needs to have. The stage can use imported elements from N.Sane Trilogy, since the art style can fit in Ultimate fine. Crash has a lot of fantastic tunes to add on the pack. It is expected that he won’t be an echo either, of course.
-Finally, SEGA: another boost to Crash is the most recent publisher of his titles on Japan, SEGA. This company is already in Smash with Sonic and Bayonetta, so they can help in a good way the contact between Sakurai and Activision, thanks to this.
If we find more, i can update this.