Novosibirsk, the biggest metro system after Moscow and S.Pb, have only 13 station in contrast to 64 of Saint Petersburg and 182 of Moscow. The other Russian cities can't do a "serious job" before further expanding of underground which may last forever with current rate of financing.
In last-soviet period (1980-90-years) large town (more 1 000 000 populations) begin consruction metro. But in 90-years XX centure is strong economic crisis. So, little metros only for decoration purpose: low financial capacity of cities.
For example, Novosibirsk is large town in Siberia. One station is building five years.
I'm agree with both posts. Also don't need to forget that the population of Moscow is 11.51 mln. people, the population of St. Petersburg - 4.87 mln, while the population of other Russian Metro cities is varies from 1.14 mln. (Kazan) to 1.47 mln. people (Novosibirsk). Accordingly, it's simply impossible to have the same passanger traffic as in Moscow or St. Petersburg.
The second factor is the unfortunate choice of route (it's actual for Metros in Nizhny Novgorod and Samara). It was relevant in 1980s, as it was projected to transport workers in industrial areas. However, after the Soviet collapse, many industrial enterprises were closed down due to financial problems and others have sharply reduced the number of staff. For example, if during Soviet years the staff of the GAZ plant in Nizhny Novgorod (it's remain one of the largest companies in the Russian automotive industry) was 120.000 people, that now this number decreased to 27.000. The reduction of workers at the plants and factories has led to a decrease of passanger traffic in Metros. The new Metro lines were not built in 1990s for the same reason - cuts in funding.
In any case, Metro is a necessary kind of transport in all seven Metro cities and the opening of new stations in five cities will lead to an increase in passenger traffic. For example, Kazan authorities planning to build two new lines, and they received financial support for this project. In Yekaterinburg two new stations will open this year. In Nizhny Novgorod, next year finally will open the first station on the other bank of the Oka River. This will lead to a long-awaited connection of the two parts of city via Metro bridge and to fast and comfortable transportation from one bank to another. Unfortunately, the prospects for two other cities (Novosibirsk and Samara) in the near future are not so optimistic.