I'm not sure I agree. Their second team is almost as good as their first and should easily beat Tunisia. That they lose tells me they have let their usual froggish mentality get the best of them yet again. In general I also think it's best to keep up the pace and just win whatever you can win, even if it doesn't matter. It's not good to relax.
I expect South Korea to manhandle Portugal for similar reasons. Already qualified, being a little lackadaisical. The question is will they be able to gas it fully when the elimination rounds start. That's gonna be true for France or Portugal, but somehow I don't suspect for Brazil.
I like teams such as Australia or the USA in the second round, but not beyond.
I don't have anything against them, I just like watching the big teams and the big players battle it out. Too many teams like them in the quarter finals and the quality of the entire tournament goes down.
Which is precisely why it might be best that Belgium exits the tournament tomorrow.
I kind of agree with that. I like seeing new blood making the top tier, however, as football has a diversity problem.

I am glad to see African nations make their case in the second round of the group stage, for example. Forza Senegal.
I don't mind when "unfamiliar" names make it deep in the tournament for those reasons. But if it mostly becomes that, you feel something is missing ... like when Porto beat Monaco for the 2004 CL final despite Porto's insane pedigree in hindsight.
How I felt about WC 2002. Turkey, South Korea, an Average Germany and Brazil in the semis.
Meh and pass
I forgot about Turkey making it that far. But some years Germany and Brazil has no business being in the semis, let alone QFs.