I guess I don't understand what a "semi-recumbent" is. I've never seen one. I ride a Sun EZ-1, and it's the best $200.00 I ever spent. I hardly ever drive anymore, unless I absolutely have to. I wouldn't trade my EZ for a Harley.
I don't know why recumbents are not more popular, but that's probably the reason so many models come and go...lack of sales. I think it is all in the marketing. The traditional bike manufacturers control the market. All bike magazines and websites are full of lean, fit racers on $1000.000+ road bikes or MTBs, wearing colorful and expensive bike clothing (unnecessary on a 'bent), and the latest expensive gear. There are seldom articles on recumbents.
That being said, I am confident that anyone who tries out a 'Bent long enough to get used to it, will prefer it over a conventional bike any day of the week. 'Bents are much more practical for general use, distance, and utility riding, and way more comfortable.