Ok. As much as is wrong with Elite (a lot of minor and major things and if you actually spend some time with the game, we could well discuss this in detail), this statement sounds like you have no idea of the game and its state at all. Unless "content" is some story driven campaign for you, then yes, the game has no content at all and will possibly never have any. In that case however, I:BS doesn't have "content" either. It seems to be a large scale PvP "arena" type of game. The "PU" part of Star Citizen or even NMS may possibly have "no content" by that definition as well, while only "Squadron 42" would have "content".
Horizons has so far brought planetary landings, is bringing crafting in Beta, which introduces substantial changes to the performance of some ships as well as many long needed changes to the mission generation (NPCs, but those are also added to the non-Horizons game). Planned and announced are ship launched fighters as next update, followed by player multi-crews and a one last update, for which no details have been announced, yet. That's a ~30€ season pass currently, after they initially sold it for a very steep (imo) 60€ (but that invariably included the base game). Buy it and you'll be able to use all those features on top of the base game (~15€ during christmas sales) indefinitely or leave it, and keep playing the base game which is still updated, e.g. with NPCs, as such fundamental changes apply universally.
That's around 30€ for a year's worth of updates with new features and content, to play for as long as you want and the servers are running.
It was made available again briefly around Gamescom last year, when they announced Horizons. But it was substantially more expensive than during the Alpha/Beta phase. Around 175€. Early supporters got it relatively cheap.
See above. You might want look out for the season 3 announcement. Maybe the lifetime pass will be available again, but it may be a lot more expensive than simply waiting for the christmas sales.