Freezing assets is simple. Seizing them is a huge pain. The EU has a hard time agreeing how to do it and who takes the liability for the Russian claims.
The EU has a hard time agreeing how to do anything, but the net effect for Russia seems about the same either way. If the 'freezing' lasts forever, what is the practical difference from the Russian perspective?
not committing now = keeping your options open. it's smart. usually who has more different available moves is in a better situation. money are not going anywhere and if EU doesn't urgently need them it's a nice bonus in future.
Unless Putin's scientists really discover a way to keep him alive forever, Russia will likely one day have a different leader and a different administration, which may be more amenable to diplomacy.
It sounds optimistic, but after Stalin came Khruschev, a much more "normal" person. Though it is true he didn't last even a decade. But there was a lot of political thaw in between, and some of this thaw survived.
Stalin to Kruschev was in a very different context. I don't see any way that Russia's next leader is someone cuddlier, unless through some forcing event.
Contexts are never quite the same. And instead of "cuddlier", I would simply say "more realistic".
It is quite obvious that Russia miscalculated heavily, and someone who wasn't part of the small team that decided to go in, and thus whose face is not at stake, may be more amenable to declaring "OK, our goals have been basically met, let us solve the rest at the negotiation table".
From what I get out of my Russian and Russia-located acquaintances, people are growing tired of this nonsense. Not yet rebellious (though some of the recent actions of the government, like messing with the civilian Internet to the point of unusability, plus mass culling of cows in Siberia, have certainly increased the total level of anger), but dead tired. There is political space to conclude this war, and the reason why it isn't happening is personal.