Are older thread starter posts locked at a certain time period?

Not that I'm aware. All threads are opened unless we specifically lock them.

 

And generally reopening old threads is poor forum etiquette if you are asking about posting in what are essentially "closed" but not actually closed 2, 3, 4 and more year old threads.

 

That is a site problem we the moderators cannot fix, the site admin who has to fix it is aware of various issues with the site but is busy with real life/family right now. Even we, the moderators, are having issues with certain functions such as for example your issue with editing the titles of sporadic threads.