Exactly why I didn't bother with these. I could never see the entire MCU line having these matching designs, and then continuing them too.
One could argue that from Iron Man to Endgame they could do them then stop but even that is a lot and I had a feeling with how random the film choices were we weren't going to see the rest come along. Maybe a couple more will come, maybe not, but one of my pet peeves of collecting is when matching designs do not continue.
Clearly these steels are nice. They are neat, simplistic and clean but unfortuntely the ball gets dropped time and time again when it comes to a 'full' matching range.
If these designs were brought out for all three Iron Man films or all three Cap films then I've got my reason to buy. It's a complete match within a wider collection but no, they just can't do it can they.
One could also argue that none of your mcu collection really matches against each other in the grand scale of things but at least the 'sets' we buy feel complete and an individual release is not part of a matching set.
Maybe it's too OCD, maybe not. It's just my personal peference and one of my very few hates collecting steels.