“In the old USSR a 10 year sentence was the maximum.”
Only techically. It was standard practice to resentence someone almost automatically to another consecutive 10 years at the end of the sentence, especially for political prisoners.
You are confused. What happened is that some brave souls did their ten years, and immediately upon release picked up with the dissent right where they left off and were arrested again on a new charge.
And of course surviving the prisons and gulags for 10 years is another matter. But in old Russian Imperial and Soviet law, 10 years was the max a judge could impose.
In America now we see 17 years for leading a protest. Even if you call it a riot that is utterly abusive. And the sentences we see now of well over 100 years are a farce and proof of our authoritarian government.
Right now Trump faces 641 years in Prison. That absurdity doesn’t happen anywhere else on earth.