I dont think so bitcoin is just in the internet,, internet money like.. dollar is hard money that can use every time,,, it is a cash you know not like bitcoin that need a transaction to send some money. and also dollar is more popular than bitcoin many people doesn't know about bitcoin so that it can't replace the dollar.
your statement is correct this time but who know future ...... future can change anything. US is printing USD without care of debt....they run QE3 few years ago.......USD value is falling and falling ..............this time USD is popular but future is BITCOIN only BITCOIN....

correct no body know about the future of USD, currently USD is too much popular there is no doubt about that fact, but no one no about the future may it become defame and bitcoin get the top position. i am sure that very soon bitcoin is going to hold the market not only the crytop market but fiat market also.