Is the lecture on traditional culture public welfare a bluff? What are the benefits behind the scenes?

Any lecture needs cost, but the cost of renting the venue, the cost of meeting materials, the salary of service personnel and so on. Therefore, apart from the public welfare lectures funded by the government, I think everything else has behind-the-scenes interests. Either manufacturers sponsor lectures for brand promotion, or manufacturers sell products and services directly through lectures. Nothing for nothing. Similarly, there are no free lectures.