Anyone that have lived in China or India knows how much people those places have.
There is already a tremendous pressure from the food those countries demand on the world. Chinese fishing fleet just obliterates anywhere they go, and they are destroying the Amazon forest in Brazil and Argentina with soya(proteins for pigs) plantations and equatorial jungles for Palm Oil.
Anything is inefficient at first, including agriculture itself. Wheat and corn grains were super small at first. At first, solar panels did cost hundreds of times more than what it does today.
Technology will improve and the future will be better.
Both India's and China's population is expected to fall significantly, It's Nigeria where large growth is still expected.
The pressure isn't necessarily so much from the people but from the appetite and trends and increase in spending money.
Unless you invent really good fake pork and fake fish made of vegetable protein you can grow in vertical farms that won't necessarily help
Anyway, it's not the most efficient way to grow food; I live in a country where they have tons of greenhouses. Also pretty energy intensive, but yields are great and predictable, meaning that despite being one of the smallest countries of the world, we're the second largest agricultural exporter in the world. Basically we do a lot with what we have. Which is also (for me) a bit unexpected given that most of the areas I've lived in and driven through is grass for cattle.