This option currently only checks for introduction year but does not take into account the year when the part availability changes. For example its possible to purchase star league tech such as DHS in 3025 even if your faction is set to "Mercenary".
Availability should depend on faction and current year, comstar would have access to DHS in 3025 but not mercenaries.
Right now using artillery in a 3025 campaign is problematic as artillery is not present in the introductory rules, but limiting parts by year still allows you to obtain all the star league era tech with no issues.
Per SO pg 178 extinct equipment is still available with a +5 to the roll, so not impossible to find just very near. Considering an elite tech has TN 5 adding all other modifiers may push most extinct equipment beyond 12, save for possible DHS and FF armor.
While the feature request is valid, it is not entirely accurate on its assumption.