Yeah, looks like titan wrecks will not remain as permanent thargoid mats farm sites. I went to Taranis this past weekend, roamed the place for +3 hours hoping to find some more Biomech Conduits (which there were plenty of a couple weeks back) and I couldn't find a single one. TIssue samples, mats for caustic sinks, hearts, sensors etc where also rather scarce.
I found three TDCs, though, that I was swifty dispossessed of by an NPC pirate the ONE minute I went to the bathroom.
Once all the maelstroms have disappeared won't the wrecks be the only source of e.g. caustic crystals (if those ever have a use)? Maybe they'll be permanent, just with a much lower drop chance than when the Titan was freshly blown.