Total subjugation is internally stable - your peasants are not that likely to revolt, but you will fall behind your more open neighbours because you'll be much less productive, and that opens you up to external threats. Tsarist Russia and other nations of the time did not really have a choice to abandon industrialization for the sake of stability, it would just have caused it to be ripped apart by the industrialized nations - perhaps sharing the fate of the Ottoman Empire or the fate of China in the Opium wars.

East Germany vs West Germany; North Korea vs South Korea - and that's in less than a century. On a longer timescale, think Ming and Qing dynasties compared to Europe on the same timeframe - China was much more stable during that time, but stability was not sufficient in the long run. However, the current PRC is perhaps a counterexample, though there is a lot of nuance, external conditions and multiple very different approaches that the China leadership tried out during the last 50 years.