Currently, there is no way to see what items exist in the world, except those that are one level above your current position. This doesn't give the player much of an incentive to go down a particular path. If you think about the real world, you know what all the big expensive thing you would like to have are, but you can't afford them yet and save up to get them. V-O should be the same.

you should also gain something at every level.

I agree with the OP. Low level players have no idea what the tree holds in terms of advances, making it difficult to decide what kind of character to develop. It may seem that there are too many items to list that way, but items could be grouped or filtered, at the option of the player [Small Weapons, Large, Equipment, Trade Goods]. The ones above your level would still be grayed out. The same should apply to ships. Lower level players hear upper level players on [100] talking about these things, but they have no idea what they are because (a) you never see any other players with that stuff and (b) you can't compare the items in the store. Not all items would be viewable in every station, so there is still an aspect of discovery (like with trade items) of which items are available where.