Early on in one of these threads I posted about an experience in Keeper of the Lake where we ended up abandoning because the DPS wasn't up to par and the healer couldn't keep us up indefinitely, and I was one of the DPS. Happened to get it again last night while on the same job.
Second time around went fine. The interesting thing is that the first time I thought my DPS was okay (since I was half of the total group DPS), until I saw my number the second time had nearly *doubled*. Turned out I was also part of the problem in the first group. It looked fine compared to people in the group but I was actually making some serious BRD mistakes that I've been able to work on since then and it really showed in the return visit. I'm not even close to a top tier player, but that's a huge gain and it helps make any run I'm in go more smoothly, so I'm really happy.
That's where the value in a comparative analysis comes in vs a personal only parser, in that it provides some context to figure out what X means. Without that, you're running half-blind because you have a number but no context and no way to do a proper analysis with it.
That said, SE probably won't add one because they're in the perfect spot right now. The tool exists if you want access to it (albeit it you need assistance if you play on PS4). SE has rules to ban people who cause problems with it, and otherwise they can ignore it. It costs them nothing in development budget. With how much stuff they want to do and how often budget is an issue, is it worth taking someone off stuff like glamour system improvements to implement what can already be provided if you google how to do it? Let alone the ongoing testing and maintenance costs bringing it into the game would require.
For them, the status quo works.