Power-aware routing algorithms in Wireless Sensor Networks (WSNs) aim to solve the key issue of prolonging the lifetime of resource-constrained ad-hoc sensor nodes. Contemporary WSN routing algorithm designs have severe limitations on their scalability; that is, large-scale deployments of WSNs result in relatively shorter lifetimes, as compared to small-scale deployments, primarily owing to rapid sink node isolation caused by the quick battery exhaustion of nodes that are close to the sink. In this paper, we analyze the scalability limitations of conventional routing algorithms and compare them to those of our recently proposed Hybrid Multi-hop routing (HYMN) . We mathematically analyze HYMN and show the relationship between network size and routing algorithm scalability. Additionally, through extensive simulations, we show that HYMN scales considerably better in terms of network connectivity.