it can happen, as time goes on. blockchain technology continues to be developed for real life. blockchain is about notes. even I think, it's not only a notary. but there will be many things about traditional records that will be changed to the blockchain system. certificates, financial records, state documents, even national elections can be carried out by blockchain ... so we are heading towards that.
One thing for sure, nothing is certain in life. If Blockchain technology becomes widely successful within the mainstream world, you could expect many of today's jobs to go extinct in the future. It's been proven that Blockchain is a real useful "tool" for proving the authenticity of documents, ownership, and more. This way, Blockchain technology can replace many traditional notaries of today. The only thing it lacks is legal recognition within the mainstream world. Still though, Blockchain tech is incapable of meeting the demands of everyday users because of its scalability issues. In this sense, notaries have a huge advantage over Blockchain (in addition to being state-backed).
If Blockchain never replaces notaries, there should be nothing to worry about. After all, Blockchain works better for finance than anything else. Notaries might end up using Blockchain technology in the future, if the same handles its limitations. This outcome is more likely to happen in the long run, than Blockchain replacing notaries in their entirety. Time will tell us if people will demand notary services using automated systems powered by Blockchain tech and AI, or continue in the traditional path where an actual person does all the work for you of notarizing your utmost important documents. Just my opinion