I guess that's the problem.
That's too bad. There are better ways to make money in this game than exploration. Faction reputation would have been a good incentive to keep doing it.
Also, it makes no sense to me that Universal Cartographics is totally unaware of a Federation controlled system, full of populated planets, stations and hundreds of traders flying around, and needs you to discover it for them.
It would make a bit more sense that a small faction didn't know about a system controlled by another small faction, and they are willing to buy the data (in exchange of credits and a reputation bump).
When you sell the data for inhabited systems, same as for systems that have already been scanned, all you are doing is selling them up to date data for which they pay you a lesser amount (and of course it also allows new players to still make a little money from the trading of exploration data for systems that have already been scanned a million times).
So, while its a little dubious in terms of lore, its certainly a good design in terms of new player friendliness.
As for it not affecting your faction - once again, you are not selling the data to the faction, you are selling to UC. And i think if you asked most explorers they don't even care about the in-game benefits of exploration. Sure, the money is a nice benefit, but there are much better ways of making money if that is your goal.
I can see some career opportunities that will generate no money, but still be lots of fun to play. For example, a journalist.
