I don't have data, but I do have anecdotal evidence to contradict #1.
I live in upstate NY, where farm land is cheap (in relative terms). We are seeing an influx of Amish, who can no longer afford land in Ohio and Pennsylvania. (To be clear, they might be able to afford land, but at such a cost as to risk the enterprise and family. The Amish won't do that.)
We are also seeing new farmers moving here from states such as Wisconsin. They have family in those states, but they can't afford the startup costs including land. Here they can.
I think land costs are more complicated than you make out.
You can start farming on land that you lease. When you have enough hardware and capital you start buying gradually. Starting as a farmer is very difficult but not for these reasons alone. Learning craft is super difficult. Sometimes you have one shot during a season to try something. My parent had higher education, where born into families with farming traditions but still took a decade to master vegetable production.
Amish cannot afford land because they suck at farming. They lack education and intentionally do not use modern farming techniques.
Shipping produce from northern Australia to the Americas or Europe is going to mean you'll either have a bunch of spoiled produce, or produce that was picked far too early and has no taste or nutritional value. Are you planning to ship food by jet to deal with this?
To put this into context for me, what cost do you call 'cheap'? And that land they're being outpriced from, how much does that sell for?
For comparison, agricultural land in the Netherlands is around 50-60k euros (60-70k USD) per hectare, so about half that per acre; in Belgium it's a little bit less but not much. When I look at those prices and do some back of the envelope calculations, my mind boggles at the efficiency they need to make enough to pay back the loans to buy this land in the first place (I do enough work in agricultural economics to know that it's more complicated than that at the micro scale, but still, overall, someone has to make money).
I don't know about that guy's area, but near me in Michigan, which has a similar climate as NY, you can find decent land for $9K per hectacre easy, possibly cheaper.
Wow. That's in stark contrast to across the lake in Southern Ontario. Good farmland has been selling for upwards of $20,000 CAD/acre, or about $30,000 USD/hectare.
I live in upstate NY, where farm land is cheap (in relative terms). We are seeing an influx of Amish, who can no longer afford land in Ohio and Pennsylvania. (To be clear, they might be able to afford land, but at such a cost as to risk the enterprise and family. The Amish won't do that.)
We are also seeing new farmers moving here from states such as Wisconsin. They have family in those states, but they can't afford the startup costs including land. Here they can.
I think land costs are more complicated than you make out.