So what´s supposed to happen if the US "cedes" Europe to Putin??? Are Russian tanks going to roll into Paris, or is Putin going to dominate them economically with Russia´s mighty economic strength? Will they invade and defeat them the way they did with Afghanistan. Somehow I think a European would look at you and ask wtf are you talking about us being "ceded" to Putin?
And what would a ceded "Asia" to China look like? They´re just going to roll over?
All hypothetical, but Putin with a free hand on Europe could see the whole region destabilised. All the major powers like UK, France and Germany now spend a fraction of their GDP far less than what America does on military budget, and it's entirely feasible that if they can't count on American support, they will increase spending on this area due to Russian aggression. If you see nothing wrong with an arm race in Europe, and the fact that with their military superiority, Russia can be free to encroach on Eastern Europe the same way they did in Crimea or Georgia, then yes, silly me.
On Asia, this isn't even a question. Without US presence in the region, developing countries like Vietnam, Indonesia, Malaysia, Phillipines etc... will have their economic and even geographical sovereignty imposed upon by China, in the case of Vietnam/Myanmar, land and Vietnam, Phillipines, Taiwan etc.. the South China Sea. Cheap Chinese goods of dubious quality, most of the time downright toxic will flood these countries market, harming consumers, local companies will be put out of business due to their Chinese counterparts, I can go on and on. Human rights will certainly go down the toilet without a US-led UN warning dictators, and Chinese current strain of racism and Islamophobia threaten the security of the region as a whole, as well as their tendency to disregard others' borders, be it Tibetan, India, Myanmar, Vietnam etc..
And even if you disregard all of that, it's not in the US interest to cede Asia. It's the fastest growing region both demographically and economically. It's a great source for labor and new market for US corporations. Why would any responsible policy maker let China have sole control over it and put the US under a competitive disadvantage?