Better to have it and not need it, than to need it and not have it!
Well, except that there are HUGE downsides - literally - to a later model Tundra.
The biggest downside is that it's big - as in, would likely not fit in my garage (because I would need a double cab to be able to carry passengers.)
Big also means big (read: "Expensive") tires and wheels. It hurt paying $850 for the tires on my 4runner, I can only imagine the raping my checking account would take when it comes time to reskin a Tundra. I doubt I could get out of there for less than a grand.
Also, big would limit my ability to go off road. Over on White Rim, there were a few very tight turns that would have been extremely not-fun with a long, wide, heavy vehicle like a Tundra.
It's also big in
cost - it would bust my $18k budget by about $10k, minimum (and most likely more - I doubt I could find a decent double cab 4x4 Tundra for under $30k.)
If I was pulling a 5th wheel or even a large double-axle travel trailer of course I would get a full size vehicle but considering that our teardrop is the heaviest thing I'm likely to tow for any distance, there's no point in anything as large as a Tundra.