Karnage
I-am-a-pirate. I do not need credentials!
ahem the 737-900ERs are our newest 737s (~10 years average), so they aren't going anywhere for a bit.
The -10Max is meant to be a 757 replacement, and you could hear me laughing from here, etc.
The MAX10s were also going to allow retirement of at least some of the older 737-800s. But thanks to delays those 800s got sent to overhaul and will be here til 2030something.