I've noticed a lot of small markets signing off mostly VHF/some UHF stations that have been on the air for up to 50 years with a big four affiliate (CBS, NBC, ABC, and Fox) and replacing them with a lesser known network (CW, Me-TV, Heroes and Icons, etc.). One that comes to mind would be Tallahassee, in which former Fox KTLH moved to WTWC-DT2 and replaced with Me-TV. I know there are others like I know a former CBS station on channel 4 shut off and replaced with Heroes and Icons but I can't remember any others at the moment.
The reason you are seeing this is because the FCC is cracking down on JSA's/LMA's...basically forbidding them. That is why owners have to be "creative" with how they work with the programming when they buy stations or companies. Buy the programming from the station they "cant" own and move it to their own station. Then sell the station to someone else or move a non big 4 onto the main. Thats the thing. You can't own 2 of the top 4 in the same market. But there are workarounds for that
-2 of the top 4 stations in the market owned by same people on different RF stations? NOPE
-2 of the top 4 stations in the market owned by same people on same RF station? YUP
-2 of the top 4 stations in the market owned by same people with 1 on a full power and 1 on a LP? YUP
As for the "workaround" I think Gray Broadcasting was kinda the first one to figure out the "loophole". Back late 2013-early 2014 when they bought Hoak Media it gave them 3 duopolies
Lincoln/Grand Island, NE with KOLN/KGIN (CBS) and KHAS (NBC)
Western ND with NBC and FOX
Fargo/Grand Forks area with KVLY NBC and KXJB CBS (which Hoak was running)
When the FCC cracked down on these Hoak figured "well lets move it to a sub of a station we own"
So they shut down KHAS and moved NBC to a sub of KGIN/KOLN AND their co-owned KSNB. This one was real sneaky as they bought KSNB under a "failing station" waiver and put My Network on it. Once they owned it fully they put NBC on that. The reason for the subchannel too is because KSNB is on RF4 and between Lincoln and Grand Island so an outdoor antenna is needed. KHAS was sold and is now Sonlife.
In Western ND they kept NBC (Hoak owned all the NBC's in ND) and moved FOX to a sub. The former Fox station was sold and now is Heroes and Icons (yes on a -1)
In Fargo they kept KVLY (for the reason above) and moved CBS (downconverted to 720p) to a sub. They sold KXJB to a guy who renamed it KRDK and is now loaded up with diginets (10 of them) This move benefited Fargo OTA folks the most as they went from 11 OTA stations to now 23 now (ABC and FOX have added subs since then too)
The other way they have done it is to buy a low powered station from someone (which does not count towards FCC rules). In Wausau, WI they bought a LP and moved FOX to the LP station (they also have it in SD on their CBS station too)
Sinclair has done this in other areas too. Buy the rights to programming, move it to their own station, then in most areas sell it to Howard Stirk Holdings who runs the stations. Sinclair still has some "pull" as they will put Sinclair stations like Comet on those stations.
Thats why the Nexstar/Media General sale is taking so long to be officially approved. There were some conflicts that Nexstar has to take care of first.