I think in space, the area will be at a premium,

Why? I worry you may think this because you can't stop thinking of it in
the terms you've seen on Star Trek and elsewhe that living in space
will
mean living in small metal rooms.

Hmmm - you may be right.

Maybe the habitat which had to construct 100x the agricultural area might
make the money back from immigrants who are actually willing to live in
the
habitat and eat its food. To assume that the algae habitat might be
economically competitive is to assume some pretty remarkable advancements
in
making algae seem like the kind of food most people prefer to eat.

I think the question is, is expanding the 'crop area' by a factor of 100
harder(*) than making algae palatable. Today, I don't think this question is
answerable.

(*) harder = more difficult, more costly, etc.

Why would do you view food generation as having harder constraints in
space?
In a sufficiently-high orbit, sunlight is available continuously.

But water and essential nutrients aren't, and the cost of getting them there
could be high. Right now, we could ponder a 'algae hab' for a small number
of people, but we're (IMHO) a century away at least from an O'Neill colony.
IOW, I could see the algae hab someday, but at best, I'd be pushing up the
O'Neill crops!

Regards,

-Dave Boll
http://www.daveboll.com/