Having worked in the industry in the recent past there are some things I think people are missing.
I do not believe that MarineDepot was very successful. There has been writing on the wall from an industry perspective that they had shrinking margins and might not be around. MarineDepot switched to contract warehouses and stopped doing their logistics in house. This is convenient but expensive, A large part of this was driven buy the cost of doing business in California, MarineDepot Employees have told me this. Many MarineDepot long term employees have left in the last several years and gone to BRS or SaltwaterAquairum.com. Vendors have mentioned that MarineDepot has been later and later paying their bills and that sales volume has fallen. If it wasn't for the pandemic I thought MarineDepot might just go away on its own.
I believe BRS saw a great deal and took it. The question is why. Given that MarineDepot was using contract warehouses. I doubt BRS will have Georgia and Nevada distribution centers. They could just hire their own contract warehouses. MarineDepot was never as geeky and this may represent a move towards BRS having more entry level products. I was surprised when BRS started carrying brands like reefbreeders but it may be the case that the only way for BRS to gain more market share is for them to expand into lower end products and possibly freshwater items.
To be honest I also question the profitability of BRS. The advertising and customer support cost a fortune and the insider knowledge is that higher end products have lower margins than entry level ones. BRS also specializes in many products that are likely loss leaders due to freight. Salt, Frozen Food, Rock, and Substrate are all near impossible to make a profit on after freight and yet BRS really pushes them.
I strongly feel that the BRS founders likely always planned on selling out after gaining market share. Today market share can mean more than profit.