Hmmm .... I "sort of" find that to be the case. The California Bay Laurel leaves I get are very fresh - the trees grow all around here and it's easy to just pluck a few leaves. They are very intensely flavored, to the point of almost being too intense and oily. Even the leaves purchased in the markets have that intensity .
Now the Turkish leaves are generally nowhere near as fresh - even the fresh ones are a little older than the local Bay Laurel leaves - and lack that intense aroma and flavor. But, imo, their flavor, while milder, is more rounded and deeper, and the leaves lend themselves better to cooking.
I've recently found a source for fresher Turkish leaves, and am excited about trying them. I've not yet purchased them. They are supposed to be "almost like picking them from the tree
There's an anecdote that I came across that is worth mentioning:
"San Francisco chef Judy Rodgers recalls as a young cookthinking, 'If one bay leaf is good, more are better.' Shedoesn't remember how many she put in a duck braise, justthat 'When I pulled that puppy out of the oven at quarter to6, it was terrible. You could not eat it. It was like biting intoan Excedrin.'So for a bouquet garni for a braise or stew, as a rule,Rodgers warns, one bay leaf will do."