In the end it is Microsoft's problem, since they are the ones that are losing valid SMTP traffic. If a sufficient amount of users are experiencing a loss of e-mail as a result, then they will be forced to fix it.
There is almost never any valid reason to block an entire ip address. Single user accounts (e-mail addresses), maybe, if compromised.
E-mail, as a standard, is still pretty straight forward. Ideally you should be able to send e-mail directly from your laptop IP, if approved to send e-mail on behalf of your e-mail account / host name. Decentralization is important.
There is almost never any valid reason to block an entire ip address. Single user accounts (e-mail addresses), maybe, if compromised.
E-mail, as a standard, is still pretty straight forward. Ideally you should be able to send e-mail directly from your laptop IP, if approved to send e-mail on behalf of your e-mail account / host name. Decentralization is important.