This seems backwards to me, unless they mean that in addition to removing the pews, they're going to fill all the previously vacant space with chairs.
As a general rule, pews hold more people than a similar array of chairs, because you can put more people into the pews just by having them sit closer together. With chairs, each person takes a "chair-sized" space, regardless of the person's size.
I speak from personal experience . . . our former ECUSA church was built in the 60s when Episcopalians were taking a page from VCII . . . it was a "church in the round" with no choir, no organ . . . and bucket seats instead of pews. Supposedly the symbolism was "each person's individuality before God" -- but it meant you couldn't tuck your children under your wing during the service.
When the sanctuary was renovated a few years ago, they put pews in. My husband was head usher at the time, and he said it increased the capacity of the church significantly. Not double or anything like that, but maybe 30 percent. If there're little kids (or good friends) they hardly take up any space in a pew, where with the bus stop seats every kid had to have his own chair.
You're right, of course, as so many 'wreckovated' catholic churches discovered after making a similar move. And ... wood endures much longer than fabric.
Milwaukee Cathedral after wreckovation.
(seating capacity dropped from 720 to 694)