Some people still only consider their prestige in life so they don't want to work on existing agricultural land and there are even some people who are willing to sell agricultural land to buy other buildings that they don't use to make any production. That is why several exporting countries have previously become importing countries at this point and I am not at all surprised by this because now most people prefer to work in a relaxed manner without wanting to work harder due to the prestige being considered.
People will do anything in order to make money, if they can make a lot money in agriculture, they wouldn't sell their lands and work in someone companies. Prestige could be one of many reasons, but it's not really the main reason. I believe there are many risks or reasons why they're not continue their farm.
There's no problem if exporting countries become importing countries, this mean the other countries are better for farming about the cost, effectiveness, weather etc.