I think that's venturing into tinfoil hat territory. More likely telemetry told them that some percentage > 50 always toggle the bookmark bar off and they decided to make it the default. It's still there on new tabs after all. Companies like Google are long term greedy, they don't make unpopular UX decisions for scraps.
It's true though. You see something similar with the address bar: Chrome's is pretty horrible for accessing history or bookmarks, it instead tries to push you to do a search. Firefox has much richer information here.
I think both tags and folders would confuse people. I'd personally like them to remove folders and have only tags, but you can already imagine the HN comments ... google screwing with bookmarks to make you use search more ... not compatible with other browsers (import/export) ... monopolistic ... lock-in.
