Amadeus reinvests heavily in R&D, with a spend equivalent to its #3 competitor's total revenue. This creates a widening technology and product gap that smaller players cannot bridge, fortifying its market leadership and making it increasingly difficult for others to keep up.

Businesses become critically dependent on platforms for even a small fraction of their revenue (e.g., 20%). This 'monopsony power' creates a stronger lock-in than user network effects, as losing that customer base can bankrupt the business.

Initially, Microsoft's go-to-market strategy was not to displace competitors but to displace customers' own internal development teams. They framed their software's price as a fraction of a company's fixed in-house engineering budget, a powerful value proposition that defined a new category of B2B sales.

The stickiest software is critical but inexpensive relative to a customer's overall budget, like payroll services. This 'Goldilocks zone' makes the software too small a cost for C-suite review, yet too embedded to easily replace, creating a powerful moat.

AI models are not an immediate threat to Excel because they are designed for approximation, not the precise computation required for financial and data analysis. Their 'black box' nature also contrasts with a spreadsheet's core value proposition: transparent, verifiable calculations that users can trust.

GE serves two distinct customers: powerful airframers for the initial sale and a fragmented base of hundreds of airlines for aftermarket services. This split forces new entrants to solve a '3D puzzle' of satisfying both technically demanding OEMs and a global user base simultaneously, creating an immense and durable barrier to entry.

The personal computing revolution was ignited not by the Apple II computer itself, but by VisiCalc, the first spreadsheet program. This demonstrated a crucial market lesson: a single, indispensable piece of software (a 'killer app') can create the demand for an entire hardware platform.

Doximity integrates multiple workflow tools like telehealth and e-signatures. While specialized competitors might offer better individual products, Doximity wins by providing a convenient, all-in-one platform that doctors are already engaged with daily, creating a powerful defensive moat.

Amadeus was formed by major airlines to create a neutral distribution system. This origin story provided immediate scale, credibility, and deep industry integration, creating a powerful competitive moat from day one that would be nearly impossible for a startup to replicate.