You could just as easily argue 20Mbps is fine for these as well for many use cases - but being completely honest here running a webserver or mail server on a residential home connection is an incredibly stupid thing to do.
Why is running a web server or mail server off a residential home connection incredibly stupid?
You could say the same about putting your data in the cloud where you have no control.......
Anybody who thinks running a mail server these days is easy clearly doesn't run one. The issues of dealing with spam filtering and importantly protecting your IP from ending up on RBL lists (which will pretty much kill your email totally until it's resolved) make it an ongoing issue. It's why most smart people have moved things like their Exchange Servers to cloud based Exchange providers.
Likewise running a small website sounds like a great idea until you're the victim of a DDoS and find your RSP disconnecting your Internet connection.
I also don't understand why you think having stuff in the cloud means "no control". I have full control and backups of all my data stored in the cloud.