No, because there are entire classes of regional/intercity* trains that Germany is providing with the 49EUR ticket that can't even exist within Luxembourg. A German going 100km may well still be within Germany, a Luxembourger going 100k is now on an international trip, one that Luxembourg's free tickets obviously don't cover.
The further trains go, generally the more expensive tickets are, because you get fewer economies of scale compared to local trips within a metro area, and infrastructure upkeep is probably more expensive for such long trips through more remote areas.
Are you using "intercity" literally, as in "between cities"?
Intercity (IC) is a specific type of train in Germany, which (aside from some edge cases) you can't use with the 49€ ticket. I think you're thinking of the REs (RE is short for Regionalexpress), those go between cities too, but make more stops in smaller towns etc, and those are included in the ticket.
