There are authorized dealers who are not John Deere directly, but they are completely subservient to John Deere (they have to be otherwise they will not get access to the software tooling required to fix equipment), the semantic difference to a farmer is inconsequential, you will be overcharged[1] and scalped because the consequences of not paying is a multi-million-dollar heap of scrap because you cannot fix it yourself.
There are no independent tools to work on this equipment because selling a license to a 3rd party software would be in breach 1201 of the DMCA
[1]: https://apnews.com/article/john-deere-repair-lawsuit-settlem... [2]: https://apnews.com/article/deere-farm-repair-tractors-monopo...
One of these days I'm going to buy one to restore, the way other men but the cars of their youth.
That entirely depends on your business goals. If you want to leverage debt to amass wealth you need scale to eke out a living after the debt burden takes most of your potential profit. The 4020 is going to fall well short of what is required there. Those who see farming as an income source rather than a wealth generator, however, don't need scale and can do quite well with the venerable 4020. Eight rows is plenty when you don't have the bank breathing down your neck wondering if you are going to cover your six figure loan payment this month.
It's a lot like the business of tech, really. Some want to build the startup that never turns a profit but sells for billions years into the future, while others want to build the small "mom and pop" that offers a lifestyle, even if it never makes them rich. Both are valid and viable approaches. It depends on what you want out of it.