I prefer your reasoned argument to some pithy meme.
I understand what you're saying and I think it just illustrates a dichotomy of thinking about this. I respect the other point of view you bring.
I think the coaches know their job well enough to identify the right players for their system and put them in position to play meaningful snaps, without needing to rely on retreads. I also see the last few seasons as showing that the team has consistently had the next man up ready to play and contribute. Empirically, I find that evidence hard to ignore when considering our set up for the coming season, particularly as I've heard the cry of 'Who's the backup? We need better!' each of those last few seasons. Turned out just fine.
I do have to disagree with your idea that our depth is only excellent if the backup steps in and start to outplay the starter. That's a bit of a nonsense, the starter is ahead of them for a reason, at least at that point in time. If their career arcs are heading in opposite directions, then sure, the coaches will be looking to the future at the position, but often times, the backup is the backup for good reason. Expecting to have a third, redundant starter is not all that realistic in the salary cap era. You work to get better all the time, but that doesn't mean you have starter calibre players all over your bench.
I think we've done this dance often enough to know we hold different views. I am comfortable with mine, I sense you're comfortable with yours. Let's reconvene in December after D'Marco (or Baun?) gets called on to be next man up, as will surely happen at some point.