It's obviously a complicated domain, but I think it is dishonest to say that it is transparency issue. It's not like BLS keeps adjustment methodologies secret.
An alternative approach to tracking CPI through scraping e-commerce. They get effectively the same result.
I've seen many comments dismiss the CPI as if it was somehow broken. The real problem is that the CPI is correct and that there is no inflation. Stock gains are either driven by a bubble or simply through unfair government policies or both at the same time.