As answered by our moderator in this thread, and our administrator in one of the threads you linked, we process hundreds of tickets per day. We are constantly working to improve our flow and avoid missing issues, but we are a small team doing our best.
(I think it is also worth highlighting that the examples you provide above are years old, and do not reflect the increase in support staff nor any other process we have implemented to improve our support desk flow. Additionally, the support ticket you filed with us is less than 12 hours old, it seems that you opened this topic within minutes of filing your ticket, and thus you did not really give us a fair opportunity to get back to your ticket in the first place.)
As highlighted by hechelion earlier as well, I have also personally begun tracking and pushing up support issues that are posted in the forum in order to optimize this process further, but I also have a multiude of roles at itch.io, and as an average human being, I only have so many man-hours in the day, as do the rest of our staff that works on processing support tickets. We naturally have to prioritize cases the higher priority they are, and certain matters require far more attention than others (for example, search indexing, while important, is much lower on our priority list compared to managing account issues, payment issues, addressing game reports, or anything that requires our immediate intervention; search indexing is only one part of the site, and we highly recommend that your promotional efforts be focused towards off-site promotion, rather than relying on being indexed into the new releases section, which is commonly highly populated and has new content being added to it basically every few minutes).
Thanks for your patience!