Arbitrum: Leadership in the Layer 2 Ecosystem and Future Challenges @arbitrum continues to maintain the largest ecosystem and active user engagement among Ethereum-based Layer 2 networks as of October 2025. The daily active addresses fluctuate between approximately 175,000 and 450,000, with daily transaction volumes consistently exceeding 3 million. Multiple chains are expanding under the Orbit framework centered around Arbitrum One, with specialized chains such as Gravity, Proof of Play, and ApeChain emerging. Major DeFi protocols like Uniswap, GMX, and Aave are all built on Arbitrum, and various projects are active in gaming, infrastructure, and consumer applications. Additionally, several grant programs and an Orbit chain revenue-based developer guild are in operation to strengthen the developer ecosystem, facilitating the active migration of new rollups and projects. From a technical perspective, the Stylus multi-VM allows developers to write smart contracts not only in Solidity but also in Rust, C, and C++, significantly expanding the developer base. The Orbit framework enables rapid deployment of custom L2 or L3 chains and supports the configuration of gas tokens, governance, and data availability. Timeboost is a technology that determines transaction order through an auction mechanism to reduce MEV and improve UX, recording approximately $2 million in revenue over the past three months. Furthermore, collaboration with Succinct Labs is underway for the integration of modular ZK proofs, evolving into a hybrid rollup model that enhances withdrawal speed and security. The governance structure aims for decentralization. The Arbitrum DAO directly decides on protocol upgrades, finances, and validator composition, effectively functioning as a check, as seen in the past rejection of the AIP-1 proposal. While the sequencer remains centralized, the BoLD protocol, aimed at permissionless validation, is operating on the testnet with a mainnet transition planned for 2025. There is a security committee for emergency responses, but its composition may change based on DAO decisions. Compared to competitors, Coinbase's Base currently slightly surpasses Arbitrum in terms of TVL, but Arbitrum maintains a broader DeFi ecosystem and mature governance. It holds advantages over Optimism in TVL, transaction volume, and user count, with ARB holders granted more direct authority in governance. ZK rollup projects offer rapid finality and low costs technically, but Arbitrum's optimistic rollup model is still regarded as the most stable and compatible solution. From the user perspective, despite significantly reduced bridging costs, the still complex UX acts as a barrier to entry. Users must navigate multiple wallet networks, and the variety of bridge UIs fragments the user experience. However, Fast Withdrawals and composable USDC are gradually improving these issues. Gas costs are still affected by Ethereum L1 congestion, but costs and MEV are being reduced through Timeboost and batching, with further savings expected as EIP-4844 is implemented and ZK integration accelerates. Interoperability is still under improvement, with solutions like Layer Leap, Chain Mesh, and CCTP being developed to simplify asset movement across chains. Activity metrics indicate an increase in pure users without incentives. The 2-month retention rate is about 37%, maintaining around 29% after 12 months, with DeFi activity showing recovery with daily DEX trading volumes exceeding $1 billion and TVL over $4 billion. As of May 2025, protocol revenue exceeded $214.9 million, with major contributors being Circle, Aethir, Uniswap, and GMX. The perpetual futures and DEX sectors show particularly high user retention rates, demonstrating greater loyalty than the options sector. Risk factors include sequencer centralization, DAO operational risks, technological obsolescence, and lack of token utility. A single point of failure in the sequencer still exists, posing a potential vulnerability until the BoLD protocol achieves full decentralization. Governance has improved since the early AIP-1 controversy, but issues such as reduced ARB delegation and voting participation rates are noted. The rapid advancement of ZK rollups exerts pressure for technological catch-up, and falling behind in account abstraction or cross-chain standard adoption could lead to a loss of competitiveness. The ARB token has low practical use due to the absence of gas or revenue distribution functions, but recent discussions on fee sharing and staking-based governance improvements are actively ongoing. Key metrics include a total TVL of approximately $4.1 billion as of September 2025, daily active addresses between 175,000 and 450,000, transaction volumes between 2 million and 4.5 million, daily DEX trading volumes ranging from $600 million to $2.5 billion, and annual protocol revenue exceeding $200 million. Governance participation shows a decline with 246,000 delegators and 320 million delegated ARB, with about 1.1% of tokens vesting monthly, set to fully release by March 2027. In conclusion, Arbitrum's competitiveness stems from its mature ecosystem, broad developer support, DAO-centered governance, and the drive for hybrid ZK integration. However, challenges remain in sequencer centralization, declining governance participation, and responsiveness to the pace of technological innovation. Key metrics to watch moving forward include TVL, active addresses, transaction volumes, protocol revenue, governance participation rates, and the gradual introduction of sequencer decentralization and ZK capabilities. In summary, Arbitrum remains at the center of the Layer 2 ecosystem, but it must maintain the pace of decentralization and technological innovation to solidify its current position in an increasingly competitive environment.