Sunday afternoon games are some of the highest rating for the NFL, Sunday afternoon football is a bit of an institution in the US.
prime time is important because that’s the maximum potential viewers available, but it’s also when there’s the greatest competition from other sports and tv shows.
Watching your football team at 1pm on Sunday is a ritual in the US.
You then get the nationally televised games in prime time on Thursday night, Sunday night and Monday night.
The similar thing for us would be club rugby all being at 3pm on a Saturday. Similarly Rugby League used to play almost all their games at 3pm on Sunday. They generally had two Saturday games (an afternoon and an evening game) and a Friday night game. They've obviously split away from having games on concurrently and now have (with some variation) 1x Thursday night game, 2x Friday night games, 3x Saturday games and 2x Sunday games. None of the games tend to overlap.
Largely our ritual around test rugby is that they are on Saturday night (wasn't always that way but it has been for a long time now). In general I think we should keep that.
I agree with some other posts that doing some things midweek makes sense particularly when we are talking about games with low audiences to begin with so trying something different isn't much of a risk if it doesn't play out well.
The French series being partly midweek was good but was predicated by needing to squeeze three tests into two weeks. I'm not sure you'd sacrifice three consecutive Saturday nights (with possible an afternoon game for one of them) in a normal year. Would you have the series on three consecutive Wednesday nights? Potentially. No one will want to do three tests in two weeks without being forced to.