There are many who would like to not be beholden to anyone else for their own email, but when they try it, they quickly find it's far too much work to actually ensure that when they send an email to, say, apply for a job, it will certainly arrive.
I think not knowing is a big problem. For example, I just use docker-mailserver on a VPS with decent IP reputation and SPF set up (but not DKIM/DMARC) and haven't really had any issues with the big providers.
However, if there were issues, I wouldn't know about those myself, unless I had some code that sends emails to those providers and then checks whether they've been received periodically.
On one hand, it would be nice to have confirmation for when a mail has been handled successfully (delivered and sitting in their inbox folder, not tossed aside and not filtered as spam, regardless of whether they'll actually read it), but then again some software will also block remote content (like tracking pixels) over justified privacy concerns and bad actors would also benefit from said functionality.
That's really small amount per month but for 100K a day you can use almost any extremely low-end VPS
https://www.hetzner.com/dedicated-rootserver/matrix-ex €46.41 ($50.10 USD) rents you a single physical computer with a i5-13500 CPU, 64 GB DDR4, 2 x 512 GB NVMe SSDs.
If you want cheap dedicated servers, you can get even lower prices (though the value may not be as good): SoYouStart (OVH but in North America) has $30 dedicated servers[0], OVH in France has dedicated servers (Intel Atom tier, but still your own whole computer) for $11 a month[1].
[0] - https://www.soyoustart.com/us/essential-servers/
[1] - https://eco.us.ovhcloud.com/#filterType=range_element&filter...
In the world of dedicated, you can get so much more vs what you'd pay for the equivalent EC2 instance.
Thank you for the information.