IBIS and lens OIS are absolutely wonderful to have but as Boessu mentioned, proper technique will take care of the need for IBIS. Holding the camera correctly and when there is a heavy lens, holding the lens with one hand while shooting, arms in close to the body will stabilize any camera. Then for shooting, keep your shutter speed fast enough to cover any shake you are introducing. The 1/focal length rule is a solid starting point to compensate for any shake that you introduce. IBIS and OIS allow you to more easily shoot at speeds slower than that BUT isn't absolutely needed to do so. Cameras for decades have not had any stabilization in them and millions upon millions of pictures have been taken that are tack sharp without it.
Only two of my lens have OIS on them and I have never had IBIS in any body and I shoot weddings in low light all the time without any problems. I also shoot wildlife with long lens' and also have no problem. If I can do it, anyone can do it.