1. You can't really regulate something decentralized and world wide like crypto tokens; They can't regulate pseudo-anonymous transactions or privacy enabled transactions;
2. If the company is regularly registered in some chamber of commerce in a country, that country Government is able to regulate that company accounting books but still the company may not register it's activity on the crypto world;
But if Gov claim to regulate those registered companies another profile of investors would come to the crypto world making it stronger.
There is already a lot of third-parties firms doings ICO analysis and rating them. Govs doing their own analysis and approval of companies will not mean an investor will read their analysis and invest in scams anyways, there is no law that make investors obligated to read companies analysis and no analysis in the world that predict the future of that company being a good investment.
You bring up something I was going to write earlier.
Even if governments regulate, it doesn't mean that they will be able to enforce. China has banned its people from selling coins in ICOs. This might be enforceable. But if China bans its people from buying coins, this will be hard to enforce.
FYI, governments do not and have never analyzed companies for investors. Governments will ban companies from making promises or claims, such as: "buy our coin and it will go up in value by 200%".