The consequence of expiring the certification of courses that have not been measured for 10 years is that handful of courses (Gene says about 20 per year) will have to be remeasured once. And of that 20, how many fit the scenario that everyone is sure the course hasn't changed? 5, 10 maybe? So each year 5-10 measurers have to remeasure a course once and 5-10 race directors have to pay for it.
What's the consequence of deciding that every course that was ever measured is now a valid certified course? There will be many, many more courses throughout the country that have been changed by construction but are still certified. Expiring courses gets many of those inaccurate courses "off the books."
Yes, it does seem a little silly that we have to measure a few courses that everybody knows haven't changed since the day they were first measured. But wouldn't it seem sillier if we keep dozens and dozens of courses as certified and record-elibible even though everyone knows they have changed and are no longer accurate?