I would call this an excellent example of the fact that GDP per capita is not a reliable indicator of the standard of living of the population. You wouldn't say that the Nenets Autonomous Okrug lives twice as well as Luxembourg, would you? I like to call it the "Guyana effect" — high incomes/low population = high GDP per capita, even if the standard of living itself... not well.
Just the same, I calculated adjusted for PPP, taking into account the purchasing power of the currency - the ruble. The point here is more that the Nenets have good oil and gas reserves (the Barents Sea and the Timan-Pechora basin), while their population is ridiculously small — about 40,000 people. And we get the "Guyana effect" — high incomes/low population = high GDP per capita.
However, I think your guess is not false either — the prices are really higher there. The only thing that can prevent it is an adjustment for the undervalued ruble currency, which is why prices in Nenets are considered conditionally equal to Penza (we get the same problem as with nominal GDP). Although, in general, the standard of living of Nenets is not bad: some of this big money falls into the regional budget, but it clearly does not stand on a par with Western Europe or the Anglosphere