Adding an FPGA would make it significantly more complex, compared to the simple Logic design. The Logic 16 is substantially more expensive.
Then the simple Logic design is overly simple. An FPGA isn't
that hard to implement. No, you're not going to fit it into a case the size of an iPod Nano anymore, but why should even a "basic" logic analyzer fit in something that small anyway? They used to be bench equipment...
(Speaking of which, I wonder what fraction of the price covers that wanky custom anodized aluminum case. I don't imagine they're made in very large quantity.)
If you want a true fully-featured LA you can find used HP ones selling for less than a new Saleae-8.
It really amazes me how cheap these sell. I guess a lot of people just don't see a use for one, so there's not as much of a market for them...?
Except that you will certainly have exceeded the $150 by the time you bought pods.
I've seen at least a few of them sold fully equipped for a similar price, and that's just with casual browsing.