There has been a lot of work done on ruggedizing Low Observables by reducing the reliance on coatings and by baking RAM into the skin of the aircraft. Furthermore, margins have been built in so that you can have LO features degraded yet still meet requirements for signature.
http://4.bp.blogspot.com/-LpX_1hV40aY/T ... ief+LM.jpg
On the F-22, they went from a signature-based approach to a combat effectiveness based approach after a while and would only restore RCS before it became a hindrance to overall combat effectiveness and this helped boost readiness. But the F-22 is a nearly 30-year-old design so a lot has advanced since then.
The point though is an important one. Much like we went with a couple of radios and a legacy radar, to EO/IR+RF active and passive sensors, multi-band data-links and voice communications, video downlink capability etc..signature reduction measures boost capability and as such much like anything else you have to invest to maintain that advantage. This then leads to a system to measure the RCS over the course of day to day operations and then develop strategies to restore it in a timely and cost-effective fashion. This has also created a role that did not exist with operational squadrons in the past which is one more thing operators must prepare themselves when introducing a LO capability into their fleets. It is also a lot different when you go from a silver bullet fleet (F-22, B-2 for eg.) to a LO design being the staple of your air-force.