It’s not about elevation 100% of the time. The reason we go up higher is to get the yew that’s growing in a less than hospitable circumstances; it’s colder, sorter growing season, harsher weather with huge amounts of weight from the snow, etc. Which in turn grow strong or die, only the resilient survive. Above 3000’ yew is more scarce but it’s there and the wood is very fine ringed, dense and TOUGH. Between 1500’-2500’ is where I find really good specimens. Lower elevations can also produce decent staves as well, they won’t be as dense and some are even too brittle. But nonetheless yew is yew and has been the premier bow wood for centuries for a reason.
But that also doesn’t mean it’s ‘bollocks’ since higher elevation yew is more often than not finer ringed, darker and generally denser.
Your ocean yew more than likely isn’t liking the salty air and the granulated sediment soil it’s growing in.
The natives in our area would use ocean yew for making tools and such but not for bows, even they would head up away from the ocean and up high to find what they would call suitable wood. Weather or not is was based on build principles or ceremonial reasons is unclear but I think it’s a little of both.
Also the way you season your wood matters, but let’s leave it at that.