As an experiment, I asked a bunch of people I know that are under 25 and not developers if they use Microsoft Outlook- the defacto email program of corporate america. The response I got was consistant.
Me: "You know... for email".
U25: "Is that new? I use Gmail (yahoo, hotmail)"- effectively: web based mail-it's all they use.
The ones who did know what Outlook was were developers and they didn't really answer when I asked the question, they just sneered.
In the startup world, everyone I know uses Google Domains and Gmail (we do).
Gmail. The new Outlook?