Product/Market Fit: "Should I 'fit' the Gospel to my people?"

The idea of “product/market fit” is well known in business startup literature. Marc Andreessen was probably the first to use the phrase, saying “product/market fit means being in a good market with a product that can satisfy the market.”
In business terms: you may have a great widget. But if your widget doesn’t solve a problem that people want to solve, or the market’s not big enough to buy enough widgets to sustain your business, the business won’t last.
If we can learn things from “business startup” literature to apply to pioneer mission startups and movements, how does the core concept of “product/market fit” work in?
Obviously, the first simple answer is: we don’t change the Gospel.
I suggest “product/market fit” is similar to the concept of contextualization. This can be a hotly debated topic, especially when we wander into the area of appearing to change (or even actually changing) the Gospel to fit the cultural norms of the market.
Nevertheless, it remains true: if the “living out of the Gospel” in the lives of a particular people group makes no change in their lives, it won’t be sustained (and theologically it really wasn’t the Gospel). And, if the cultural form of the church (meeting spaces, forms, language, what have you) doesn’t “fit” the market, it won’t be sustained either.
“Product/Market Fit” can be summed up in this old saying: “When you can put your church on the back of my camel, then I will think that Christianity is meant for us Somalis.” Or, going back further to the genesis of Wycliffe Bible Translators: “If your God is so smart, why can’t he speak my language?”
I don’t think the “product” is the Gospel. And, I don’t think the “product” is the Church – in the sense of the global church, or the idea of the church as an ekklesia, etc.
I think the “product” we must work on is the specific, localized form of the church – the delivery/sustaining mechanism – the methodology for making disciples. In this sense, what has product/market fit in the market that is America will not necessarily have product/market fit in a city in Asia.
All of the business literature agrees: if you don’t have product/market fit, you won’t have an explosively viral product. Sean Ellis has suggested you have fit if “40% of surveyed existing customers say they would be ‘very disappointed’ if they no longer had access to the service.” Lean Experiments are designed to help people iterate around finding product/market fit.
When growth rates are stagnant, and there is a huge, barely tapped market, I don’t think we should be adverse to iterating (tweaking portions of our existing church/outreach structure) or even pivoting to a whole new structure. If growth rates are less than 2%, then what we presently have is not only not working, but is actually causing us to lose.