I do not think it is a reason to be proud (unless you are Nintendo, I guess), but then again, the small snippet you posted does not indicate pride anyway. The higher price stability of Nintendo games means they retain resale value, so buying Nintendo games is a smaller risk than buying other AAA titles close to launch. Moreover, as a buyer, you can safely buy at launch without having to worry about overpaying just for a month or to of advance play. The disadvantage is, that, if you enjoy the game and want to keep it, you will pretty much have to pay 40-70€ to play it, no matter when.
Now for a positive interpretation that one can come to: The higher price stability of Nintendo games indicates that those games retain their value in the eyes of the customer, so their qualities are perceived as more timeless, because people are actually willing to pay full price years later, which is rarely the case for many other AAA games. It can also point towards a stronger uniqueness factor, because if the market was flooded with games in the same vein as Nintendo titles, the competition would be more fierce and as such a price battle may ensue. Alternatively, if you want to interpret it more negatively, Ninendo may just be very careful about supply and artifically shotening supply of their games in order to keep demand high in comparison to supply.
There are plenty reasons to like or dislike the price stability and to see them as a strength or weakness.