Let me send you a Lathe . . . you have 65 years to build me '72 Charger.
Going a little off topic here Colt. You are comparing apples with oranges, but ok, you send Adacas a lathe and you want your Dodge ´72 Charger.
Lets say Adacas take his time to learn machining, and how to get all the necessary parts to machine and assemble your Dodge Charger. He spends basically almost all his free time to learn how to assemble the car from the smallest piece, and tries to get the parts wherever he can, or machine them if not. I assume 15 years? 20 maybe? 25 if he spend sometime making a family perhaps.
Now, instead of Adacas you have a multi-planetary government. A government that already have companies that make similar products. In fact, they began with already a partially factory for BA, and got lucky and hired an ex-Irian scientist to lead the teams that finally get their first product in 3084, 66 years before 3150, the present in-game time. Also to that, add that nation already have samples of that "'72 Chager" since the Civil War era, so about 24 years prior to their own locally produced BA. And after that, that nation, togheter with only other 2 (and one is confirmed to possess the only known factory of that "Charger"), are almost the only nation to continually have that unit in their MUL roosters since the Civil War.
Those that means they have a factory for that product? I don't know, maybe they have tons and tons of salvage that they keep in working condition for almost 100 years. But the situation is similar to when i noticed the Taurian Royal Thunderbolt and Marauder (later confirmed by a writer, and much later by the RecGuides).
And to this add a new faction that get access to the Purifier, the Scorpion Empire, that gets it in the Dark Age era, probably after conquering the Hanseatic League, that had a confirmed Purifier line in Falsterbo (HDF Manufacturing, Operational Turning Points: Hanseatic Crusade, page 4).
So, to resume with enough time, dedication and money you can complete your personal projects, and probably the MH (and the TC) have either a truckload of Purifiers lying around, or they got a source for those BAs.