Sometimes migrating the advanced SOAP services is not an option at all. CXF provides the production-quality environment for SOAP and RESTful web services be developed and combined if needed.
The real world Java-based web services projects will often combine all sort of web services, some of them written using JAX-WS and some JAX-RS. One obvious option for combining JAX-WS and JAX-RS services in CXF is to register multiple JAX-WS and JAX-RS service endpoints all referencing the same service bean. The SOAP WS and REST approaches are different but nothing prevents JAX-WS and JAX-RS service beans delegating to some shared implementation, for example, the one reading or writing data to the database.
Often enough, the SOAP developers who would like to experiment with JAX-RS or make their SOAP services more HTTP-centric, wish to reuse the same code serving both SOAP and plain HTTP requests. CXF lets do the combinataion using either the Java-First or WSDL-first approach.