That's what I was seeing as well. We've used a pretty innovative racking system from Osprey a couple of times. It's actually pretty impressive how well it handles uneven terrain. It's pricey but as has been mentioned if you really take a look at the total cost, particularly when you're paying contractors to dig footings and pour concrete it's not that bad.
Zero mechanical civil work was required at any of the sites we did them at. We did use a shovel and get the top 3" of grass out of the way from under the footplates.
Big adjustments happen with telescoping legs that pin into place and the fine adjustments happen with something akin to a trailer jack.
No concrete or ballast, they are held down with "duckbill anchors".
No affiliation with them in anyway, just sharing this as something that I found really interesting.