Just looking at Morgan Dollars, looks like NGC hasn't updated their coin values in 8 years or more? It isn't just low graded circulated coins, it's even more noticable in MS categories.
Honestly, I think all the price guides are very outdated right now. Inflation I'm sure plays a part in it but I think they're just out of date versus reality. Around 2014 I would have told you they're all high retail prices in the guides. Meaning higher than Street price for the most part. Now I think they're 10 or 20% lower than reality, at least as far as eBay prices, coin dealer prices, and great collections. This might be the first time in my lifetime that the price guide prices are actually lower. I can't think of another time or collectible where this would be the case, but I feel confident it's true for coins right now for NGC, PCGS, CACG graded coins with average to above average eye appeal.
I still see coins where the price guide is higher (noticed it yesterday when looking up several random examples on GC). I think the biggest contributor (at least on the lower dollar end) has been the rapid rise in gold and silver prices. For example, a few weeks ago we basically got to the point where all the common date Morgans had more melt value than guide up to MS 63. Also, post-2020 the coin market has had a strong run. We temporarily bottomed out in late 2019/early 2020 and that was probably the last time price guides were consistently high (I was tracking MS 65 Morgans and they got down to about $85 in greysheet and sales were concluding on GC in the $70-$95 range).
For the items based on melt prices, yes it should be easy. For items that use an average of sales, not necessarily as it still takes human intervention to toss out the wrong results (for example, PCGS coinfacts still links to sales of the wrong coin at times because the eBay description was incorrect...an example I've seen is where it pulls a gold coin instead of a silver for the silver guide).