The most logical explanation is that the event was ordered by the " Deep State", and the hit was done by a German EU asset working in Porton Down. Had the Russians done it, then it would have been a professional hit, not the amateur botch up that one expects from EU "assets". There is no conceivable reason for the Russians to have done it, by the way.
That is the only explanation that fits all of the "facts" that have come to light.
Could you explain in a little more detail? Why wouldn't the Russians have any motivation? Didn't Skripal betray Russia? What would make Germans want to kill him? The article I shared implies that they've identified several Russians that were involved in the assassination attempt. You don't believe that? What makes you think that Russian assassins are better than Germans?
A simple cost-benefit analysis would show that clearly, a blatent poisoning like this has much more damage back home than it does good. Putin isn't stupid, if he really wanted revenge then he would do it in a way that wouldn't point all the evidence back to him. Russians are certainly not clumsy when it comes to spy work.
So who did it then? Well the "evidence" that the poison came from Siberia is far from damning--anyone can waltz across the border to Kazakhstan and then hop on the next flight to London with a bit in his pocket. But it certainly is a good way to lay the blame on someone...
You didn't really answer as to why you think the Russians are better at assassinations than the Germans. Why do you think the Germans would do it at all? If they did, they perhaps they did a pretty damn good job, if they made it seems like the Russians did it. If Putin is so concerned about damage being done "back home", why isn't he more forthcoming in helping in the investigation? It sounds like you watch a lot of Russian propaganda. You write as if you think it's impossible for the Russian government to do something stupid.