The main reason why businesses and large corporate companies have not accepted Bitcoin, has to do with government regulations. A business cannot accept Bitcoin as "legal tender"... if their local government have not approved it.
So, this is the barrier that are placed by governments to protect their local currencies. The reason why they are protecting their local currencies are simple, because they have full control over it. (How much is printed... who owns it.... how much they own... how they spend it... etc..)

Government regulations prevent businesses from accepting Bitcoin as legal tender, primarily because they aim to safeguard their local currencies. Governments exert control over their currencies, including issuance, ownership, and spending, ensuring stability and economic control.
Accepting decentralized cryptocurrencies like Bitcoin challenges this authority, as they lack government backing and oversight. Consequently, until governments approve and regulate cryptocurrencies, businesses are reluctant to adopt them as widely accepted forms of payment.