Rehoboth said "I do think the brothers knew how to run the business but they didn't know how to grow the business."
I was going to disagree with you on the basis that the business as it existed before Lemonis arrived was only earning 4% on sales and did not have up-to-date equipment.
But the brothers did take $160,000 and turn it into a business valued between $540,000 and $810,000* after 11 years. This is a compound annual growth rate of between 11.3% and 15.6%. That's a great return assuming that they have been paid a salary every year. If they were not able to draw a salary, then this CAGR is less impressive because they were subsidizing it and their actual investment is higher than $160,000.
*$810,000 from Lemonis' offer of $270,000 for 1/3 of the company. $540,000 just to provide a lower range of value assuming that Lemonis' final offer was somehow generous ($540k is not that far off Lemonis' initial valuation of $160k to pay back Keith & Tina plus $270 for the company).