Any thoughts on could radiation oncology become obsolete in the near future?

Doubt it: Radiation oncology is a fairly important part of the medical field. Their expertise is vital in treat patient with cancer. There are certain procedures that i as a neurosurgeon perform together together with radiation oncologists, like gamma knife radiosurgery.

Radiation : Radiation is a unique treatment as it works by different mechanisms than chemotherapy and it can be delivered to very specific locations in a noninvasive way. With improvements in early detection and the use of high dose, stereotactic radiation, it is possible that radiation would be used more not less in the future.

Not likely: Although radiation therapy has been around for many years, it continues to be very important for the treatment of many cancer types.

Hopefully: I would believe any oncologist would be ok being out of a job when cancers are preventable & curable.