@Dreamstate I'm not really "replying" to you as much as I chose your post to hang my own thoughts off
I think there may be an expansion next year to do with atmospheric planets or other stuff.
I want atmospheric planets as much as the next guy, but I think this is at least 2 years away. It is possible that the Jurassic World work might translate to populate worlds with flora and fauna (imagine being chased by a T-Rex like beast in your SRV!) but even so it would still be a lot of work to integrate that in, and Elite has the additional issue that you have to render those assets from space and during the transition to landing, which is not an issue JW has to deal with.
Additionally I think Space legs is at least 3 years away, because I cannot see that it adds any real gameplay to Elite until we can get out on said atmospheric/inhabited planets. You might argue for an FPS mini-game akin to Arena to come sooner, but I don't think the majority of existing Elite players would be all that excited about this, so I don't see it as a high priority for Frontier. The other tack you might take is to argue for boarding of player ships.. but this sort of PvP focussed gameplay also doesn't seem to be the sort of gameplay the majority of current players want (at least from where I'm sitting). This is, I think, why we're seeing Beyond updates to Mining and Exploration (in addition to those gameplay areas not seeing much love as yet).
On the topic of "season 3".. I suspect the reason "Beyond" is not a season and is free is because it's
mainly core gameplay updates and things that the community might well have expected (and Frontier wanted) to be there on day 1. Essentially I think that charging for it would have "annoyed" enough of the community that it's just not "worth it" and so instead they opted for the "win" which comes from "giving it away" (ultimately this is an investment which will return more in the long term by having more (heavily invested) players).
Don't mistake me here, I'm not suggesting anything underhanded in this decision. I suspect it was prompted by the generosity Frontier have shown the community time and again
in addition to being a sensible business decision. If Frontier were in a position where they really needed the revenue then despite wanting to "give it away" they might have been forced into charging for it. But as they're in a very strong position they can afford to "invest" the work now for the long term benefit, which is just good news for all of us loyal fans.
Of course, being a lifetime expansion holder I do briefly wonder why I bothered

.. not seriously of course. David said himself at the Frontier Expo in response to Qs; He feels that Frontier have really "only just begun" with Elite Dangerous so my lifetime expansion will cover many more years of updates and features to come.