For shopping? Amazon makes money on both ends, from the buyers and the sellers. The sellers pay to put their stuff in premier locations in the search results (and it's not always first). The janky ass search function is a profitable feature for Amazon that let's them obscure what you're really looking for in the hopes that you'll give up and buy the thing in front of you.
If Amazon was a grocery store, and you went to buy eggs, you might look up at the signs on the wall to find eggs, and walk towards that spot. But what if the store knew where you were heading, and placed other stuff in your way. How about some egg substitutes that you have to climb over? And here are organic duck eggs that are more expensive but get great reviews. Also, did you need butter? People who buy eggs also buy butter. No? Ok, here's the display with regular chicken eggs. These are $4 a dozen, and over here we have these at $4.25 a dozen, and those are $6 a dozen, and they all have exactly the same packaging. Did you need them this week or can you wait until these ship next month? The $6 eggs have great reviews, and did you need butter? You picked the $4.25 eggs which should arrive in a few days. Pay no attention to the dozen eggs that were $3.25 and shipped free.
Why has nobody made a better search option? Because Amazon doesn't want it to exist.