"established expert" is a correct and usable phrase in written English.
You might use it to describe someone who is reputable and knowledgeable in a specific field, for example: "John Smith is an established expert in economics and has written several bestselling books on the subject."
Mr. Wood's firm was the only one considered in the area of commercial leasing, in which several lawyers said he was known as an established expert.
This study established expert, consensus-based research priorities for patient safety in emergency medicine.
Equality is encouraged, so that for example a young student would feel free to question the views of an established expert.
Bidding does boost your authority on that topic and makes it much more likely that your tweet will appear in results, but if a well established expert in the field is tweeting about the same topic, their tweets might appear above your sponsored tweet.
Would a junior investigator feel reluctant to challenge the views of an established expert?
Quantitative assessment was made by Martine Salane, an established expert in the techniques of measuring mammographic density [ 41].
Indeed, Chinese culture discourages the challenging of conventional wisdom or critiquing established experts.
This same pattern is going to emerge in the organisation where the established experts will hotly contest new ideas that go against their intuition.
One of the amazing things about Wikipedia is how it has emboldened anonymous volunteers with the same power as established experts.
Ten teams from across the US benefited from training, materials and resources, mentoring, advice from established Experts in Leadership Development (ELDers), and seed funding to develop, run, and refine their own career development workshops for women in STEM academia.
But rather than seeking out views of established experts in the field, he had Lu and only Lu answer the question he posed.
