Depends on what type of stone.
Created white lab diamonds aren’t marketable yet.
Fancy colored are.
Lab rubies and sapphires: honestly the Lab created ones can be better than naturals depending on the process and cutting used.
Some do a very good job of recreating the very top naturals for a lot less money.
The flux process created ones are the top material and combine it with precise cutting and you have something that it would be extremely hard to find a natural to match.
On the other hand take one that is made using the flame fusion process and crudely cut and it matches the low end naturals with bad cut jobs.