How AI Threatens the Giants of Consulting
AI Isn't Just Disrupting Consulting, It's Dismantling the Walls Around It
For decades, scale was the moat that protected the giants of consulting. McKinsey, Bain, BCG, and the Big Four Deloitte, EY, KPMG, and PwC relied on armies of junior consultants to take on large, complex projects that smaller firms simply couldn't staff. That advantage is now eroding fast, and AI is the reason.
At Data Tribes, we encountered this compelling piece from the Financial Times and felt it deserved a closer look, especially for anyone working in professional services, data, or AI advisory across the region.
The New Challengers Are Already Here
A wave of AI-native advisory firms is launching across the UK, founded by veteran Big Four partners who see a window that didn't exist before. Firms like Queen's Tower Advisory and Unity Advisory are built from the ground up around AI agents that amplify small, senior-heavy teams, operating at a scale that once required hundreds of people.
Queen's Tower founder Mark Bunker, a former Deloitte senior partner, describes the model clearly: teams made up of 20% humans and 80% AI agents, creating what he calls an "amplification factor" that brings a 20-person firm to the effective capacity of 150.
Private equity is accelerating this. Europe's largest private capital group has committed over €500mn to build out tax advisory firm WTS, which aims to hire 100 partners within five years and directly compete with the Big Four.
Three Foundations of the Old Model Are Cracking
The article identifies three pillars of traditional consulting that AI is actively undermining.
The Generalist Model: Much of what generalist consultants did is now handled by AI. Clients arrive with an AI-generated diagnosis already in hand and only need deep specialists to go the next layer down. Firms with niche expertise are winning more work.
The Billable Hour: When AI can review thousands of contracts in minutes, billing by the hour stops making sense. McKinsey now ties roughly a third of its work to performance-based fees. Clients increasingly demand outcome-linked pricing.
The Pyramid Structure: The traditional model relied on large cohorts of junior staff whose hours funded a smaller number of senior partners. With AI reducing the need for labour-intensive delivery, that pyramid is losing its economic logic. Leaner "obelisk" or "hourglass" structures are emerging instead.
What the Incumbents Are Doing
The big firms aren't standing still. BCG reports that 40% of its revenues now come from AI and tech-focused work. KPMG created an internal "air-gapped" unit called Project Watts to bypass slow approval processes and build AI tools in weeks rather than months. McKinsey has formed alliances with major technology companies rather than building everything in-house.
But rolling out AI tools across organisations with hundreds of thousands of employees is slow. And there is a new competitive threat from an unexpected direction: OpenAI and Anthropic are moving directly into the enterprise advisory market, potentially bypassing consultants altogether.
Who Is Most at Risk?
The article makes a sharp point that resonates for the region: the most exposed firms are not the Big Four or the boutique disruptors. It's the mid-tier firms caught in the middle. They lack the Big Four's capital to invest aggressively in AI infrastructure, and they lack the agility of boutique firms. Squeezed from both ends, they risk being stranded.
Bottom Line
The MCA estimates that smaller, AI-enabled firms are already seeing growth rates of up to 50% as they compete with larger rivals. The shift is real, but its full impact may take years to fully materialize, with client loyalty to established brands still acting as a buffer.
The firms that will lead the next decade of professional services are those willing to rebuild around AI from first principles, not just layer it on top of old structures.
