When scraping amazon reviews I always hit a wall at 5,000 reviews even when the product has 40,000. Is there any way to get past this barrier and scrape more?
To obtain more pages when scraping directly from search results, you can use filters to divide the search into smaller parts. For example reviews with star ratings may be searched first for one star, then two, etc. This of course does not promise all the results, but would increase your chances. Some filters may be more numerous but harder to implement, such as tags or usernames.
Alternately, access the data directly through their API and/or become an affiliate through their Amazon Associates program.