Meat flavor's secret it's mostly the Maillard Reaction
https://en.wikipedia.org/wiki/Maillard_reaction between heme (molecule inside hemoglobin and mioglobin and also in Leghemoglobin in soy roots) that create a sequence of reactions that creates a lot of new molecules of flavors and aromas. Indded there last generation flavors called
Reaction Flavors, that tries to use Mailard Reaction to create similar flavors, but it's not 100%. Coffee have thousand of molecules of flavors, and it's also hard to mimic.
But if Heme (pattented by Impossible Foods for the production method they created using GMO Yeast to produce it) it's so important to give beef taste to soy protein burgers, I wonder why the other kinds of meat, like chicken, fish, pork, have different flavors. I will ask about it to Impossible Foods. If they respond I will post their response here.
About lab meat, well, the cells it's one thing, but muscles have the cells, the fat, the blood and the chemical compounds from body that can get into the tissue or between cells. That's why even it had not the exact meat flavor. I suspect they will research meat flavors to add to the lab meat tissues created on laboratory, to please consumers more, when it became afforedable.
No surprise, you alread get meat flavors added to real meat for burgers, since a lot of cheap meat or cartilage are processed together to create grond beef for cheap frozen burgers pattys