Of course this is just 1 example and there would need to be a full scale analysis across all the sectors and differing metrics to assess whether or not there was a strong argument to make for using a metric such as RSI.
This unlocking of value occurs for a variety of supposed reasons, my favorite having been the fact that the more focused firms are easier to understand and analyze more thoughtfully: All else being equal, increased clarity leads to better analysis, more likely by industry experts, which boosts confidence and in turn leads to higher valuation metrics.