In my opinion manipulation on bitcoin price levels already happening like some governments are secretly buying bitcoins and to buy cheaper they might be manipulating bitcoin markets. If more governments are involving into bitcoin markets then we can obviously expect prices to go up but if one or tow countries try to grab cheaper bitcoin then they may go for manipulating prices to fish for cheaper. There are whales hence we can expect sharp down fall at anytime before we start travelling to moon and stars.

When more government start participating into bitcoin or different busies level which means we even considering such participation/suggestion as manipulation, bitcoin prices will definitely skyrocket. Government manipulation will be good whereas individual or corporate' manipulation should be avoided or need to approach them with more care.