The top obstacle to Bitcoin being mainstream is mass adoption. Bitcoin now is mainly purchased off an exchange.
If there was an option to use bitcoin as a currency for paying salaries, and calculating how many bitcoins is worth an hour's job. This would increase circulation.
As long as BTC is pegged on Fiat currencies, it will keep being used as a speculative tool.
you are absolutely right, if you stick to the fiat currency forever bitcoin will only be a speculative tool. but I think the role of government is very important if we want to make bitcoin as a mass adoption. but the reality is very difficult, so much opposition has been made by various parties.