Why is there no middle mouse click options for new Mac machines today?!?!

You are communicating with Apple users, like yourself. We are not Apple, so we can not answer questions about why Apple does or does not do something. You should direct your complaints to Apple at the following link: www.apple.com/feedback Have you checked to see if your third party mouse has supporting software available which enables the feature you want? For what it's worth I have a cheap wired Microsoft mouse I've used for years which has the scroll feature and it works with Big Sur just fine. Clearly, your problem has to be with the mouse you are using. It would appear at first glance that Apple is not taking basic features away from their high end products as you suggest.

Have a Magic Mouse 2 in old iMac circa 2012 and woks fine. To scroll place finger in middle area and can scroll, flip between pages etc. To enable - System Preference >> Mouse. There are three tabs including main page to enable various features.