Oh what a shortsighted question! 🙁
ASCII is a US only standard, hardly usable anywhere else. Ever thought about Europe? Do you really think the French, German, Scandinavian, Czech, Slovak, Slovene, Croatian, Polish, Baltic, Rumanian, Hungarian, Finish, Spanish, Portuguese people could do anything with their computers if they just used ASCII? And they have at least the Latin alphabet!
So what about the several hundred millions of people with Cyrillic alphabet? Do you really think they could use their computers if they had ASCII as the only foundation for coding their text data? And how about Asia? China probably outnumbers both all ASCII users and ASCII data volumes used anywhere in the world, and the Japanese numbers are amazing as well.
Both ASCII and EBCDIC are foundations for better systems at best. The first try was the ISO 8859 family of character sets; it still proofed to be insufficient. Meanwhile Unicode is there and becomes more and more mature. The fact that Microsoft (almost) fully supports Unicode in its modern Windows variants might make Unicode the character set used both by most users and for most data already. Of course you will find the 128 ASCII characters there as well - somewhere among the 100,000 others... 🙂