i just moved from mail to outlook and transferred 10.000+ mails from archives in less than an hour using "mail extractor pro".
smooth. an extra 50$ on top of the microsoft license, and it seems to be worth every penny.
uslsoftware who made that little wonder must be so glad for apple launching catalina.
so must microsoft.
and that might be the point: sometimes it is very good business to fix it even if it ain't broken.
apple makes money on hardware (and selling us content as music, books etc.) they do not make money updating, maintaining software as mailprograms, browsers, spreadsheets etc. securityupdates - business support... ; it´s not apples business. better let their hardware customers free to buy good software from others, and keep to the good business making money on a brand and hardware.
then they of course have to bring a browser, mailclient etc. but not anything serious you could use as a pro.
the pro is now about the look and the price tag.
( sent from my 2 days old iMacPro.. :-)