I'm not sure I agree with this assessment. 4runners are certainly off-road vehicles, however there are different types of off-roading.
In the US, the predominant off-road "mentality" typically means wranglers jacked up with with giant tires and rock-crawling. Here it is mostly about building a rig for bragging rights, then going out and proving that you can drive over certain obstacles for bragging rights. Outings are short; most might be same day, or a couple of days, but rarely are folks driving off-road for multiple days.
Outside of the US, the off-road "mentality" is over-landing OR just having a vehicle that is rugged enough to take on rugged "roads" on a daily basis (we have more paved roads in the US that an other country so not typically an issue for most Americans). The 4runner is pretty much a Prado (some videos below of the Prado going though the paces), and if you watch reviews outside of the US people will rave about how good it is out of the box, how it is the "benchmark" for 4x4 testing, and all you might need is a slight lift and different tires to make it perfect for overlanding (which many folks on here do to their 4runners). I think everyone needs to digest that a statement....the Prado(4runner) is the
benchmark for 4x4 testing outside of the US. That is a pretty bold statement to make, and outside of the US a sizable amount of people agree with this characterization.
Watching videos from Australia and South Africa will make folks understand that the 4runner is an overland/rough road vehicle, not a rock crawler. Yes, people do that with theirs, and it certainly can be capable if you invest in rock rails, and some armor, but it is rather large to do that (and really that is what wranglers are for). When it comes to off-road, the 4runner is really about transporting people and equipment on long overland journeys, or just traversing rough/rutted/muddy roads, or driving on the beach to get to off the beaten path for a day trip.
In summary, there are many different types of off roading, even with a stock 4runner you can do a heck of a lot, and yes the 4runner is an off-road vehicle

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https://www.youtube.com/watch?v=Oyqhtd84XVY
https://www.youtube.com/watch?v=52_0EluDwVc
Just a hilux and fortuner video...again I'm always impressed at what vehicles are capable of "stock".
https://www.youtube.com/watch?v=qfi68CR0RIA
https://www.youtube.com/watch?v=0FsXmDWznWY