It depends if one is talking about teenagers and non-professionals, or professional people. Professional people use website, in a big way. And email - email is by far the dominant form of communication in business.

I agree that teenagers, college students, and working non-professionals jump from platform to platform to communicate. Meanwhile the professional work world is pretty steadfast.

The professional work world has platforms too, such as Slack and Jira and Confluence many niche platforms. But there are almost always websites that form the backbone of an organizaiton's information tree, linking to platform pages as needed. And a lot of professional people are finding that messaging/collaboration systems like Teams/Slack are not so great afterall - e.g., it is hard to "CC" someone outside the organization - and people are now deciding what to communicate via email and what to put into a slack message.