I don’t think it’s just because they are non-competition matches. I think it’s that there are too many of them in that category. Back in the day, occasional friendly matches, particularly against decent opposition, still felt like they mattered. I remember a Germany game not long after Italia 90 that certainly fell in that category.
And someone made the comparison with rugby and cricket where internationals matter more. Even though large numbers of those aren’t in a competition. Okay, I know they are trying to contrive something for the autumn rugby series going forwards, and there has been something equally nonsensical for test cricket for about six years. But prior to that, not a single cricket test match was part of a formal competition (except in 1912) and nor were most rugby internationals and they still mattered.
What has certainly changed since I first started watching football, even at club level, is that individual matches don’t seem to matter anymore. We used to enjoy them as a thing in their own right. The individual result could stand alone. But such is the obsession now with the Premier League, whether it’s getting to it, or staying in it, that this isn’t true anymore. Thats why the cups have declined too. And friendly internationals are the ultimate one off match.