i agree. physical money is still the way most transactions are normally done every single day. it's government ran. it's accessible to most people. it doesn't need online connection. bitcoin is good for transferring money and doing online transactions but it still is dependent on whether there is online access. compared to fiat, which as you've said is how most transactions were done, bitcoin would require a lot more to be fully accepted and i think with how things are going now, fiat would still be the major form of currency that we will all have even in the future
But even fiat needs an internet connection. For example, if you want to withdraw from the bank, you are unable to do so if there's no internet connection. Maybe your statement is true only to people that use cash (or fiat's physical form) but not to people that mainly use card to buy things.
Mass adoption is the only answer to your problem - bitcoin not getting accepted by everybody. As for you, it doesn't have to be literally everybody but only people that you transact with. You can influence your business partners or people that you always do cash transaction with to try bitcoins.
Yes fiat may also need internet i you want to use all the features and use its all advantages but its not neccessary to use internet for fiat.
Specially i see in my country approx 60% of people in my country doesnt ever used internet but they are using fiat and never needed internet for that where as for bitcoins,internet usage is neccessary.