Russia could perhaps develop a more effective agricultural economy over the decades, but only if protectionism isolates it from low cost, high quality imports at all times, Russia cannot compete in agriculture in the open market largely because there is no incentive to compete with abroad as long as Russia’s natural resource exports are so valuable. Huge investments are required in educating farmers, in rationalizing, extensifying and intensifying farming and in distribution infrastructure to bring products to the market on time. Considering the current layout of the Russian economy no such vast sums can be diverted or effectively invested at short notice.
Many if not most Russians grow much of their own food: potatoes and vegetables. For what these need supplemented it’ll be possible to substitute imports with local alternatives but they’ll be far, far more expensive. And, they’re not of the quality, diversity and low price that urban Russians in the cities nowadays take for granted. Also it’ll be difficult to feed the big cities in Russia in winter when agricultural areas turn into a deep freeze.
This is another Putin mistake, the ban needs to disappear before winter sets in. Maybe Putin’s game plan will have played out by then, an invasion of Ukraine is probably not possible after september anyway.