Arguments for the pursuit of enlightenment assuming nonexistence of rebirth

Recently, I came across an intriguing opinion - Buddha did not believe in rebirth and that his views on the topic stem from some fake suttas. It sparked a thought in my mind that I believe strongly contradict this viewpoint. I wanted to share it with you, and also open it for counter arguments. The argument is structured as follows: if rebirth does not exist, we only live one life, and once we die, we cease to exist. Therefore, what motivation would a person have to renounce worldly attachments and endure the hardships of seeking enlightenment? One might argue that individuals pursue enlightenment to alleviate their suffering. However, it's worth noting that many people lead relatively comfortable lives, experiencing only brief periods of discomfort and ultimately facing death. In fact, those in higher social strata often enjoy luxurious lives and many find fulfillment in them. Given this context, there is no objective reason for them to even considering renouncing their comfortable existence in pursuit of enlightenment? Therefore, if there is no rebirth, enlightenment becomes optional - much like learning mathematics, whcih although is beautiful, is nonetheless optional. We could potentially choose to live our lives and simply "power through" until the end, and be done forever. Or even worse, kill self and be “at peace” forever. If that were a solution, Buddha (assuming he was smart and well intentioned) would have proposed pursuit of enlightenment only to people in bad mental/physical conditions - but he did it universally - which says that its not true. This reasoning is quite convincing to me. I would appreciate hearing any arguments towards non-existence of rebirth and significance of enlightenment assuming it. Your insights are very much appreciated.