What you describe is basically event sourcing, which is definitely popular. However, for OLAP, you will still want a copy of your data that only has the actual dimensions of interest, and not their history - and the easiest way to create that copy and to keep it in sync with your events is via triggers.
Business processes and the database systems I described (and built) have existed before event sourcing was invented. I had built what is essentially event sourcing using nothing more than database tables, views, and stored procedures.
