In most growing businesses the sales approach was never designed. It grew. The founder sold the first customers, a few good people were hired, and each of them built a private way of working. That holds while the market is kind and the founder is in every important meeting. Then you add people, add a product, enter a new city, and the same effort stops producing the same result. Nothing has broken. There was simply never a decision about who you sell to, how you reach them, and what the team is meant to do each week.
Why it persists. It persists because everyone inside the function is busy selling. Stepping back to look at the whole system is nobody's daily job, and the things that need deciding — segments, coverage, structure, process, capability — sit across people who each own only one of them. So the business fixes what is visible instead: another hire, another lead source, another target. Each fix is reasonable on its own, and none of them changes the shape of the system that produced the problem.
If it stays unresolved. Left alone, the gap widens with every addition. New joiners are trained by watching, so the same habits copy forward into a bigger team. Competitors who settled their model earlier take the accounts you both wanted. By the time revenue clearly stalls, the correction costs a year of hiring, a churned team and customer relationships that are hard to win back.