Great. Russian revenue from gas and oil fell considerably since the start of the war.

How many years does it typically take for crippling sanctions to bring a country crawling to the bargaining table?

Be careful of the goal. Sanctions are unlikely to directly bring someone to the bargaining table. Sanctions make is harder to get the things Russia needs to fight way. It will take years to catch up, but Russia has a smaller economy. Russia has mostly stopped using tanks because they can only make a few of them (1-3 per day depending on what source you ask), and they have no ability to make more, sanctions are part of this.

The real question is what if there were none - Russia would have more money and thus have done a lot more damage to Ukraine - but there is no way to measure damage they could have done.

> The point of sanctions is just to slightly reduce Russian government revenue. In combination with other measures this provides some leverage in negotiations over a peace settlement.

The words you apparently missed from what GP wrote are: "slightly reduce" and "some leverage". Nobody said that sanctions end wars or bring about peace negotiations on their own.

The idea is to incessantly put pressure on their economy until it breaks or adapts. At which point you put more pressure until they become the DPRK or Iran.

Right, that would be a good outcome. North Korea and Iran are annoyances but not existential threats and they have minimal capability to project power far outside their borders. The goal should be to cripple and impoverish Russia through a sustained policy of maximum cruelty that includes everything short of kinetic attacks.