Preliminary case data on Omicron seems to indicate the reinfection risk may be higher than we saw with Delta. South Africa seemingly had a high population immunity after its recent Delta wave, but cases subsequently have surged as Omicron became dominant. This would be consistent with immune escape of prior infection immunity.
We don't know the extent of this immune escape, and it doesn't necessarily follow that it would also apply to the vaccines, especially the boosted. Over the next few weeks the picture on vaccine protection will become clearer.
Oklahoma's state health department has tracked reinfection rates in the state versus vaccine breakthrough cases over time. Pre-Delta the rate difference was ~6-9x higher for prior infection immunity. Post-Delta it decreased, but was still higher for prior infection by ~2x. Indicating that vaccination protection was better than prior infection immunity.
"Natural immunity" is not a strategy. As the virus mutates and antigenic drift occurs reinfection risk will increase. The previously infected should get vaccinated. CDC data indicates that vaccination after a prior infection lowers the reinfection risk over 2x. This "hybrid" immunity is quite robust.