The F-15 was initially sold only to a relatively small set of foreign operators - Israel and Japan. Saudi Arabia was added in the early 80s, but it took 20 years after that before another foreign operator was introduced.
Now, the F-15 is flown by the Israel, Japan, South Korea, Qatar, Saudi Arabia, Singapore and the USA - but SK, Qatar and Singapore were all sold the F-15 after the F-22 made its first flight.
Had F-22 production continued, it's quite possible we would have seen a similar pattern there.
EDIT: in comparison, the F-16 is operated by Belgium, Denmark, the Netherlands, Norway, Greece, Poland, Portugal, Romania, Turkey, Bahrain, Egypt, Israel, Iraq, Jordan, Oman, the UAE, Morocco, Indonesia, Pakistan, Singapore, South Korea, Taiwan, Thailand, Chile, Venezuela, and of course the USA. 26 countries vs 7.
Now, the F-15 is flown by the Israel, Japan, South Korea, Qatar, Saudi Arabia, Singapore and the USA - but SK, Qatar and Singapore were all sold the F-15 after the F-22 made its first flight.
Had F-22 production continued, it's quite possible we would have seen a similar pattern there.
EDIT: in comparison, the F-16 is operated by Belgium, Denmark, the Netherlands, Norway, Greece, Poland, Portugal, Romania, Turkey, Bahrain, Egypt, Israel, Iraq, Jordan, Oman, the UAE, Morocco, Indonesia, Pakistan, Singapore, South Korea, Taiwan, Thailand, Chile, Venezuela, and of course the USA. 26 countries vs 7.