IE11 has been in a relative state of decline for a long time. Its usage has dropped to less than 2% worldwide according to statcounter.
In the light of Microsoft announcing the end of support for Internet Explorer 11 by MS365 products and the official guidance from MS for IE11 users to migrate to MS Edge, VMware has decided to end the support for IE11 by all active versions of the vSphere Client, starting from the next update in the release line of vSphere 7.0.