You get out of IMC conditions either by:
Using an approved instrument approach most, but not all of which, are in controlled airspace and / or subject to ATC radar or procedural service. (Although there are one or two places where approaches can be made out of hours by aircraft making blind calls on the applicable frequency).
Or transitioning to VMC en-route whilst remaining above MSA.
Whilst there is no "requirement" to talk to anyone, it would be foolish indeed not to avail yourself of the best ATC service available.
We're talking common sense here - just because something is "legal" does not mean you have to do it!