If, by "universal numerical system", you mean base 10 place value notation, this system is very widely used because it's very useful. It was possibly invented twice, possibly just once (we don't know whether the early Chinese and Indian systems are independent), and spread. Base 10 systems were widespread before then (but not universal), which reduced the barrier to acceptance of base 10 place value notation.

Other systems are in use, including both older and newer systems. Non-place value systems are still used, such as Roman numerals in the West, and special names for numbers such as hundreds, thousands, millions, etc. There are still occasional uses of base 20 ("Four score and seven years ago"), base 60 (e.g., dividing degrees and hours into minutes and seconds), and base 12 (dozen, gross) systems. Binary computers have resulted in occasional use of hexadecimal notation.

If, by "universal numerical system", you mean universal use of the same symbols for the digits: 1, 2, 3, etc., this isn't the case. There are two main families of symbols for digits: those derived from Chinese digits, and those derived from Indian digits (which includes our familiar Western digits 1, 2, 3, etc.). Chinese digits are still used in China and Japan (alongside the Western digits).

The symbols used in the various numeral systems derived from the Indian system are diverse, and differ from alphabet to alphabet. While the Western digits are usually called "Arabic", Western visitors to Arabic-speaking countries are sometimes surprised to find that they can't read the digits used in Arabic. For a table showing 20 different sets of symbols in Indian-derived systems (and a few different Chinese sets), see

• https://omniglot.com/language/numerals2.htm