While "Blue Bloods" has maintained a loyal fanbase over the years, many agree that Season 13 has been a bit of a letdown. The characters appear to be spinning their wheels without any real or interesting development. If Season 14 were to truly be the last, it would give the writers an opportunity to send the Reagans off in style. They could pursue storylines they perhaps wouldn't pursue otherwise.
There's always a chance that if the team didn't agree to a pay cut, Season 14 wouldn't have happened, and Season 13 would be the final outing. Redditor u/sweetpeapickle thinks that's what the cast and crew want at the end of the day: "I think to them they want to wrap up in a nice good way, not ubruptly. And they're all willing to take the cut for that." A show that's been around for over a decade deserves a proper sendoff, and given the actors' commitment to their characters and this story, they may be all right accepting less money upfront in order to ensure the show's legacy isn't tarnished too much.
The actors' willingness to take a pay cut clearly shows this is more than just a job for them, especially for someone of Tom Selleck's caliber. As u/TakasuXAisaka suggested, "I think [Tom Selleck] doesn't care how much he gets paid. He just loves being on the show." Season 14 could be the end, or it could be just the beginning. Either way, fans are still going to tune in.