The study develops a theoretical model predicting that competitive arbitrage fragments liquidity networks above a certain intensity threshold. This model is tested using real on-chain data from Ethereum Uniswap V3 spanning 2025, which includes 2.6 million blocks. Contrary to the fragmentation hypothesis, the research finds that high-MEV periods are associated with better network connectivity and lower modularity. Furthermore, Granger causality tests indicate that network structure predicts subsequent MEV activity rather than the reverse.