65 hectares = 7,000,000 square feet, that's a heckuva lot of greenhouse to invest in just for the tiny state of Qatar.
Looking up the cost per square foot for greenhouse construction, I got a number of $7.56. That would be a $50,000,000 up-front investment cost, not even counting the maintenance or operating costs.
Since the nation of Qatar is only 2,000,000 people, that's $25 per person to make the greenhouses. This actually isn't a lot of money.
Let's take India, with 1,200,000,000 people, roughly 500 times as many people as Qatar. The upfront cost would be $30,000,000,000. That's A LOT of money for a poor country. Also you'd have to find 4.2 billion square feet of desert to construct the greenhouses. Good luck with that. On that kind of scale, the infrastructure costs like road building, trucking, maybe even rail, etc, would far eclipse the greenhouse costs.
Basically, this makes sense for a sparsely populated region, but isn't really scalable to a larger country, it seems. I'm not saying they were claiming it to be, just making the observation.