Most startups are pretty good at identifying and solving for bottlenecks, though only of one kind - operational. Usually, this is adding people to a part of the organization that's at a 100% capacity (measured in time) to ensure a speedy flow of products to market. However, there are other make-or-break bottlenecks almost no one actively solves for. 

The true bottleneck for a product company is the Intellectual Bottleneck. I realized this as I worked on a go-to-market program in a 15-people strong group of engineers, product managers, and executives, with 2 sales folks who didn't quite grasp what all the new "noise" meant. 

Put simply, your product is only as good as a seller's understanding of it/ability to communicate value in a nuanced way, or your product marketers's ability to synthesize this info to sales teams, or your product team's ability to understand and synthesize market needs and build products in a way that makes sense for the market.

This seems obvious, because it is. But it's fairly uncommon to have great teams across the board. However, this isn't just a question of good vs. bad sales team, or good vs. bad product outfits. It's about measurement, data, and optimization. 

For example, many startups aren't:
1) Ensuring engineers/product folk spend a half hour a week (or month) on listening in on sales calls
2) Measuring sales folks' product value understanding and communication consistently q-o-q

As new product capabilities, especially big ones, are rolled out, the intellectual bottleneck on the sales side adds up.Rest assured, most sales people know enough to talk about products, but usually not well enough to be nuanced in their understanding of each product.

Similarly, as new market developments, especially big ones, show up, the intellectual bottleneck on product teams can add up.

Over years, these gaps become huge. Beware!