The plug for certain companies is more of equipment that he consistently uses, and where on the bench he is. If you look, the power supply most used is one that he reviewed, and had some issues with, but the company involved did address them with upgrades, improving the product. Same with oscilloscopes, the ones most used are not the most expensive, nor the most feature packed, but the ones that have reasonable features for the use in question, and which are typically near the area. You rarely soo him using a massive multi thousand scope for measuring the blink time of a LED, but that one will be there when really complex serial decode is needed, or the really good FFT ability, or the SA it has in it as well.
The EEVblog multimeters are there as product placement though, he has to advertise the blog, the channel and the stuff that brings in his income somehow, and you cannot fault him for having a meter he was proud to put his name behind on there. like on Mailbag there was a reminder of the Teespring T shirts, which have been popular, and i have actually seen them in the wild, and wear them as well.