Is a Nintendo Switch and PC release of “Crash Bandicoot 4: It’s About Time” likely to happen?

Yes.

If the N. Sane/Spyro ports are anything to go by, then expect them to come out next year.

Check out the following: ViewerAnon’s tweet on June 21, Website source code mining by SunwerPrower, Spyro Reignited Trilogy’s 2019 ports.