Be honest: How interesting is an agency Growth Guarantee that also saves companies up to £300k p/a?

Hey guys :) My team and I have just surfaced from a 3 weeks of intensive brainstorming, planning and documenting that led to us adopting a new business model called the Fractional CGO Agency model, backed by a new guarantee: If we don't acheive any growth objectives within 6 months, we'll keep working with you for free until we do. Why? Because honestly, I'm just as sick as everyone else with "experts" who are more interested in sending invoices and dodging questions like "So what growth have you actually achieved with my money this quarter...?" than adding value and delivering real results. We realised the era of siloed marketing and sales is over and it's time to make way for holistic, company wide growth that understands and respects branding, marketing, sales and tech. All four components are so intrinsically linked that you simply cannot create predictable and sustainable growth without expertise in each area. (the kind of growth that doesn't consume your soul, early mornings, evenings and weekends!) Which means that anyone looking to build a team of less than five people is going down a path of extreme inefficiency that requires around 3x more effort and cost than a well trained, well managed team of five or more tasked with achieving the same objectives. What do you guys think?