Google's G Suite, which is still better than free web mail since you no longer have the lock-in, plus a better privacy policy, is $5 per month, which is almost the price of a Starbucks Venti Latte. And this is actually an expensive offering in the business.
So no, it's not an expensive coffee, especially since we are talking about a highly skilled and highly paid demographic.
Also I'm from Romania where we have a lower cost of living and lower wages to go with it, so seeing my Silicon Valley brethren complaining about the price of paying for non-free email on your own domain is really awkward, given the importance of email.
I get it, I hate subscriptions for software too. But not when that service is essential for your profession, your security or your privacy and email is all of the above.
A cup of coffee is a pretty lousy indication of cost. For some people going into a Starbucks for a $5/€4,40/£3,92 gluten-free-unicorn-sprinkles-ariana-grande-latte may be part of a daily routine, but for others, coffee means using a coffee-maker to brew your own cup for a few cents, or just getting a cup to go at a some kiosk.
And your email address is your online identity and has plenty of information in it that shouldn't leak, including your entire online purchasing history at least.
I am against paying for crap via subscriptions, I hate the subscriptions trend myself, but email in my opinion is fundamental to who we are and what we do online.
I almost never buy coffee out anywhere like Starbucks, but it was easy for me to understand in the context of his post
I use Tiger Technologies (https://tigertech.net) for hosting mine and my wife's personal sites and email, they are all I need for basic Wordpress/email hosting and they have a superb support team. If I decide I want to get my hands dirty with running a server, I use Vultr.
Also the much better deal is the business edition, at $10 per month, which also gives you unlimited GDrive storage. Couple that with something like ArqBackup, Rclone, etc and it gets to be very cost effective, being cheaper than a Dropbox subscription.
Also the Terms of Service for G Suite is meant for businesses and thus much better.
Just be careful when buying apps and books from Google Play. If you don't want to be locked-in, don't purchase anything that can't be migrated.
That's some expensive coffee.