Immutable protocols serve as the foundation for a truly internet native financial system. They are the public goods upon which innovative financial products and applications securely stand. By design, these foundational protocols are meant to be un-opinionated, serving the public without bias or vested interest. This architecture aims to eliminate the extractive behaviors and fees that often plague the protocol level of digital transactions. Uniswap's journey illustrates the challenge in balancing the product with the protocol primitive well; their fee switch controversy and the additional charges imposed by Uniswap Labs on users accessing the platform through their frontend highlight the friction between ideals and tokenholder desires. The essence of such protocols is to facilitate, not to hinder or profit unduly from the end user's experience.

Distinguishing between protocols and products is critical in understanding the DeFi lending landscape. Protocols are the unspoken heroes of the internet, akin to the foundational layers of TCP/IP, FTP, or SMTP. They are designed to be immutable, operating quietly behind the scenes as public goods. In contrast, products are the interfaces and experiences that users directly interact with. They can evolve, be influenced by governance decisions, and may charge fees for their services. Euler represents a notable stride towards balancing the two, offering a lending protocol that remains steadfast while supporting a dynamic product ecosystem. This equilibrium is vital for fostering trust and stability in DeFi.

The allure of DeFi's 'Decentralized Brokers' like Aave, Maker, and Compound is undeniable, with their user-friendly interfaces and capital efficiency earning them large Total Value Locked (TVL) and revenue. They've been instrumental in DeFi's growth, simplifying the complex dance of depositing and borrowing. Yet, this simplicity comes with hidden perils. Unified pools, a hallmark of these platforms, pose a significant contagion risk. A single bad collateral asset can send shockwaves through the entire system, threatening user funds with unintended risks. Governance, too, is a double-edged sword; it offers a semblance of control but often falls prey to centralization. A handful of powerful delegates can sway decisions, yet their expertise in the intricate mechanics of interest rate models and risk management may be lacking. This centralization not only skews the democratic promise of DeFi but also introduces a sluggishness in response times during crises. The Curve exploit serves as a sobering case study, illustrating how a unified pool's vulnerability can force protocols and users into precarious positions, scrambling for over-the-counter deals to prevent spiraling bad debt. It's clear that as DeFi evolves, the resilience of these lending protocols must be fortified against such systemic risks.

As DeFi matures, its lending protocols face a daunting challenge: scaling securely. The current landscape, dominated by platforms with large Total Value Locked, is not without its flaws. These platforms have been crucial in propelling DeFi to its current heights. However, they are not equipped to handle the scale and complexity of a maturing ecosystem. Enter Morpho Labs, Ajna Finance, and Euler, among others, who are pioneering a new wave of lending protocols. These innovators are returning to the core principles that DeFi was built on: immutability, decentralization, and permissionless operations. They are crafting solutions that address the inherent issues of existing systems while paving the way for sustainable growth. These new protocols are not just alternatives; they are necessary steps forward in the evolution of DeFi lending.

Each new DeFi protocol brings a fresh angle, yet they share a commitment to core principles. They anchor on a minimalistic, immutable base protocol, pushing complexity to higher layers. This approach strips back governance to the bare essentials. It shields users from the domino effect of a single asset's failure, which can ripple through a unified pool. Morpho and Euler v2 exemplify this with professionally managed vaults atop their foundational protocols. Gauntlet's move from Aave to Morpho Blue is a case in point, signaling a trend towards specialized risk management. These vaults offer varied risk profiles, giving users control over their exposure. The permissionless nature of these protocols is also unlocking new collateral options. Ajna's vaults, for instance, accept LP positions and previously sidelined tokens like $YFI as collateral. Despite their youth, these protocols are quickly gaining traction. Their flexible, open approach is likely to outpace incumbents in adopting new collateral types. This emerging class of DeFi lending protocols is poised to shake up the status quo. They stand at the threshold of widespread adoption, ready to merge safety and scalability for lending against any asset.