Picture the scene -
Frontier announce Horizons with planetary landings at Gamescon August 05 2015. It is released Dec 15 2015. Procedural planets are the Hot New Thing.
Chris Roberts releases the Pupil to Planet video Dec 16 2015, a day after Horizons launch. Kotaku report that Star Citizen is demonstrating "the game's upcoming procedurally-generated planet system" on Dec 19 2015.
Five months later Sean Tracy & Forrest Stephan do a Q&A on the planetary tech. Amongst some of the features they talk about are:
- Varying biomes
- "Amazing" atmospheric tech (scattering, like X-Plane 11 just introduced using OpenGL)
- Polar ice caps
- Mining ice sheets that regenerate
- Mining minerals at POIs on the surface
Planetary landings + mining = sales of mining ships
Planetary landings have stayed as the Big Hot New Star Citizen Feature throughout 2017, with the talk now of the square area available to explore.
Planetary landings + exploration = sales of buggies, motorbikes etc
Notice how mining has not been mentioned ONCE by CIG since May 2016, five months after Chris Roberts has it on his powerpoint for 3.0 in Dec 2016. Mining ships are not the hot new thing anymore, now you need your space motorcyle for exploration.
As to whether planetary landings will ever actually appear as an integrated feature in the PU, here's a quote from Sean Tracy from that Q&A:
"They're all working pretty much full time on the procedural planets, now we get a lot of oversight on them, we've gotta blend them into the game where they're working on the tech so just consider that when I answer any questions regarding it. I'm trying to represent it as best I can"
What they had showed for planetary landings as of May 2016 was not "blended into the game". Interesting little caveat there, as we know (and have had confirmed from CIG) that the sandworm demo was not integrated into the game either.