I feel that you are doing what most people do....and what is natural to do, and that is to overestimate the quality of players on other teams around the league and assume that we are in a horrible state compared to them. Are there any teams with 3 top tier DBs on their roster? If there is there would only be a handful at best. Most teams would be struggling to have a top Safety and a top CB.
Assuming Gilmore progresses in ability (as most assume he will) and that Byrd stays (and is healthy), we will have 2 premium DBs on the team. Obtaining another 2-3 decent (but not "good") DBs would then see us being in the upper tier of secondaries. This should be achievable with low 1st round or 2nd/3rd round drafting.....or via FA as teams like the 49ers have done.
High 1st round drafting (top 15 pick) of a DB would not be of value when considering the 2 quality DBs we already have and the long term aspects of capanomics.....unless we plan on letting Gilmore move on after his rookie contract.....or we intend to spend an unusually high percent of the cap on the secondary (compared to the rest of the league).
We certainly need better DBs, but striving for star talent in our #3,4,5 DBs is not a wise long term strategy all things considered IMO.