The inconsistency and 'laziness' of base LLMs is a major hurdle. The best application-layer companies differentiate themselves not by just wrapping a model, but by building a complex harness that ensures the right amount of intelligence is reliably applied to a specific user task, creating a defensible product.

The notion of building a business as a 'thin wrapper' around a foundational model like GPT is flawed. Truly defensible AI products, like Cursor, build numerous specific, fine-tuned models to deeply understand a user's domain. This creates a data and performance moat that a generic model cannot easily replicate, much like Salesforce was more than just a 'thin wrapper' on a database.

The best application-focused AI companies are born from a need to solve a hard research problem to deliver a superior user experience. This "application-pull" approach, seen in companies like Harvey (RAG) and Runway (models), creates a stronger moat than pursuing research for its own sake.

In a world where AI implementation is becoming cheaper, the real competitive advantage isn't speed or features. It's the accumulated knowledge gained through the difficult, iterative process of building and learning. This "pain" of figuring out what truly works for a specific problem becomes a durable moat.

Investors obsess over moats, but in a rapidly changing AI landscape, a startup's ability to quickly build and ship products that unlock latent demand is a more reliable predictor of success than any theoretical defensibility.

The enduring moat in the AI stack lies in what is hardest to replicate. Since building foundation models is significantly more difficult than building applications on top of them, the model layer is inherently more defensible and will naturally capture more value over time.

ElevenLabs' CEO sees their cutting-edge research as a temporary advantage—a 6-12 month head start. The real, long-term defensibility comes from using that time to build a superior product layer and a robust ecosystem of integrations, workflows, and brand. This strategy accepts model commoditization and focuses on building durable value on top of the technology.

Startups like ElevenLabs and Midjourney compete with large AI labs by imbuing their models with a founder's specific 'taste.' This unique aesthetic, from voice texture to image style, creates a product identity that is difficult for a general, large-scale model to replicate.

YC Partner Harsh Taggar suggests a durable competitive moat for startups exists in niche, B2B verticals like auditing or insurance. The top engineering talent at large labs like OpenAI or Anthropic are unlikely to be passionate about building these specific applications, leaving the market open for focused startups.