Publication: Will there ever be the GURPS series in PDF as compiled books?

This has happened for the Dungeon Fantasy line. It was published in revised form as a boxed game, the "Dungeon Fantasy RPG", in October 2017. In December 2018, there will soon be a Kickstarter for a reprint of the boxed game and a new bestiary.

There has also been a scenario and scenario of third parties licensed to the DFRPG, Hall of Judgment, of Gaming Ballistic. It is located in Norðlönd, a Viking-style region and culture.

Steve Jackson Games has talked about making other sets in a box, like space opera, but not recently. Given that the DFRPG has not been a great financial success so far, I would not expect other sets in cash in the short term.