I would like to clear the doubts of ‘hopefully’ and ‘beingAndNothing’ because I was making the same mistakes for comparison (a kind of parallelism) questions. I am assuming you guys are still following the thread.
The gyrfalcon, an Arctic bird of prey, has survived a close brush with extinction; its numbers are now five
times greater than when the use of DDT was sharply restricted in the early 1970's. .
(A) extinction; its numbers are now five times greater than
(B) extinction; its numbers are now five times more than
(C) extinction, their numbers now fivefold what they were
(D) extinction, now with fivefold the numbers they had
(E) extinction, now with numbers five times greater than
Here the comparison is between numbers of arctic bird now and in 1970’s. So, the answer choice A has a parallel comparison.
As for the sentence quoted by beingAndNothing -
B) Small cars today are more fuel-efficient than those in the 1980s.
It can be rewritten as
Small cars are more fuel efficient today than in the 1980’s.
It's totally acceptable in gmat to put the thing being compared(its number) before the actual comparison made between two parallel nouns/clauses( now and in 1970's) .
I hope it helped.