Tennessee is really really really likely to gain a seat in 2030 (per the Census Bureau's own estimates of its 2020 errors, Tennessee, Florida, and Texas should all have gotten an extra seat, at the expense of Minnesota, Colorado, and Rhode Island), and my guess given the absolutely bonkers pace of growth is that it's probably likelier than not that that seat will be a Nashville vote-sink.
Here's a TN with 10 seat map extrapolating the 2010-2020 pop growth. Each seat is expected to have 747k people in 2030. Growth seems to be accelerating around Nashville even though. Honestly a fair map could have a competitive Nashville suburban seat if population and partisan trends continue.
TN 2030
Rs conceding a vote sink is not necessarily inevitable.
That could happen, but the GOP will have 8 incumbents to satisfy. In 2020 all incumbents got to have a completely safe seat, that won't be the case in 2030 if they crack Nashville again.
Also we have another ~7 years of trends to go through. By that point half those districts could be competitive for all we know.
Well, the fundamental problem for Rs is the growth of Nashville and, to some degree, some level of erosion of margins in places nearby. The fundamental problem for Ds is that, besides that, they really aren't gaining in rural Tennessee. For Rs, the obvious play, if they can get their incumbents on board, is to create five rurban seats mixing Nashville and rural areas. Especially since the 2018 Senate loss margins have not been able to replicated by Ds, not even close, since...unless white evangelicals suddenly look likely to trend D, in which case, all bets are off.
