Motivational speakers, businesspersons, facilitators, and celebrities are able to garner significant earnings in speaking fees or honoraria.
[1] In contrast, speakers in academic conferences and similar events rarely get significant speaking fees or any at all.
[2] Researchers and academics consider conference presentations an honour and necessary for their careers, rather than a service.
Scientists who become popular authors or otherwise famous are an exception, and can earn similar sums as celebrities.
[3] Prudence must be taken with speaker fees for government officials or employees or to scientific searchers as it may be considered as a bribery.