It's mostly because TBC items

It's mostly because TBC items , they are more balanced, and there are numerous options for specific slots. The overall gear in Vanilla is not as famous than TBC. However, people will remember broken pieces of equipment like HoJ Reju Gem, HoJ, edgemasters, etc. which are far more powerful than other item that fits in that slot.

It's a bit more complex than "they did not know how to play at the time". They intentionally created low-level or end-game bis items, which were both disastrous, in order to allow players to make profitable and entertaining choices.

Although classic was well-known for its ability to min-max through decades of pserver experience and the best theorycrafters of all, Sims taught us that the majority of the "bis gearing options" were based on the length of the encounters with your guild were and on the specific times. Think of trinketswaps and threats against mit. Fire/frost resistance is another instance. Furthermore, many of the junk skips and encounters of naxx were enriched by special items like major recombobulator, smokey's lighter, ramstein's bolt, nifty stopwatch with a gnomish cloaking device and the electromagnetic gigaflux reactivator.

If you want to know more,you can visite https://www.mywowgold.com/