Can't disagree with that.
Both of the John Deere tractors he's talking about are in the 200 HP class.
Your Kubota is in the 50 HP class +/- and predates Tier IV emissions and most electronics.
I've seen John Deere 4960's go for big $$ at auction. They precede a lot of the electronics and emissions issues.
JD has had considerable criticism about "right to repair" because of their proprietary software. Was an on-going lawsuit last I knew.
Newer Kubota's are not much different; there are aspects of the tractor's operation that can only be fixed by connecting to a dealer's computer at their facility.