At some point in the future the cost of maintenance vs. cost of rewriting/upgrading will be so much in favor of the latter that businesses will make the (correct) choice to "go with the times" instead of spending an ever increasing amount of money and time on maintaining a code base `x` years old written in a language not officially supported/extended for `y` years, experts for which are increasingly rare (and thus expensive).

If they can find Cobol experts 50+ years after the original programs were written, they'll have no issue finding 2.7 experts 50+ years on, especially since 3 and 2.7 and more alike than different.