I don't agree with that at all. I think that Bitcoin will coincide with it if anyhting.. or take it over compeltely

Yes! Bitcoin will likely to coincide with fiat system because there are lot of rural areas around the world who doesn't have a good internet connection or aware about these modern technologies. Fiat will not be replaced by Bitcoin but it might be the second option that can resolve financial issues.
It actually there is no need to replace fiat with bitcoin or any other cryptos. Aside from having issues with internet connection but in a reason that not all of us were holding Bitcoin, in fact, those having limited resources will surely can't afford to have this.
Using bitcoin is just another option of a currency we used as it only designed like that and not intended to replace fiat in the future.