Microsoft 365 is a reasonable alternative. It's easy to buy and even tiny Customers can get a degree of real human (read: tier 1 is unhelpful contractors that you have to fight thru) support.
It's still repugnant to me, as compared to self-hosting, but I would never self-host for a greenfield SMB Customer today. The economics don't make sense and the talent pool of knowledgeable and reasonable sysadmins is dwindling by the day. (I wouldn't want to make a Customer so beholden to me if they were willing to pay for it.)
I miss being able to spin-up an on-prem email server on a box with reasonable hardware redundancy, some external USB disks to rotate for off-site backup, a UPS, a couple consumer-grade "business class" Internet connections, and a contracted "backup MX" to catch email in the event of an outage. It was a good enough for a lot of small SMBs who had a physical office, and was cheap.
