The primary drawback I see to a specialized bug out vehicle is that you can't count on it unless it is your daily driver. Like everything else I'm sure this is highly variable based on everyone's specific lifestyle but out here in the middle of nowhere you're unlikely to get a chance to run home or to storage or where ever you keep your BOV.

I had a family emergency pop up last night while I was on my way to a late dinner at a local restaurant. I needed to get out of town and on my way ASAP. The supplies that live in my daily driver and having more than half a tank of gas were the keys to responding to the issue effectively.

That said, the Mad Max mobiles are always fun to think about. grin
"There is not a man of us who does not at times need a helping hand to be stretched out to him, and then shame upon him who will not stretch out the helping hand to his brother." -Theodore Roosevelt