Massive MIMO is a key enabler for next-generation wireless networks; however, it faces scalability challenges due to power amplifier (PA) nonlinearity. This paper establishes a theoretical foundation for the inherent advantage of the distributed MIMO (D-MIMO) architecture in relaxing PA linearity requirements. While our prior indoor measurements empirically demonstrated reduced nonlinear power leakage in distributed topologies, this work develops a generalized analytical model that captures the fundamental geometric principles underlying these benefits. Through rigorous analysis, we show that D-MIMO's spatial distribution provides higher effective channel gain, enabling identical performance targets to be met with substantially lower transmit power compared to co-located architectures across diverse propagation environments. This power reduction allows PAs to operate in more linear regions with higher output backoff, thereby tolerating more severe nonlinearity without performance degradation. Simulation results validate the analysis, demonstrating that D-MIMO achieves up to an 89% transmit power reduction and maintains superior output back-off (OBO) performance across rural to urban environments, confirming its dual advantage of enabling cheaper PAs and lowering energy costs.