It's definitely the best option available in Russia. There are a couple of big factors working in favor of KPRF here.

First, a lot of people who lived in USSR are still alive, and generally have good things to say about it. Many still see USSR as the high point for Russia, and feel that a state run economy produces better outcomes than markets. There simply isn't the same level of anti communist propaganda as there is in the west.

Here's a recent poll from Russia:

75% of Russians have expressed increasingly positive opinions about the Soviet Union over the years. Only a small portion of those surveyed said they had negative associations with the Soviet Union. The economic deficit, long lines and coupons were named by 4% of respondents each, while the Iron Curtain, economic stagnation and political repressions were named by 1% each, the Levada Center said.

And here's another poll showing that most people think the Soviet economic system was more correct

Second, Russia is now increasingly falling into China's orbit and people are seeing what the Communist party managed to achieve there. It doesn't escape people that that if different decisions were made in the 90s, USSR could've followed a similar path to China. It's very likely that KPRF will continue gaining legitimacy going forward, and Russia will eventually end up with a system similar to China.