Textron would love to orphan their piston fleet.
They are still selling 172s like hotcakes at a Denny's restaurant.
A few figures from the
GAMA Statisical Databook, 1.4c Worldwide Piston-Engine Airplane Shipments by Manufacturer (2005–2018)
For that period, the peak year for piston engine airplane deliveries was 2016 at 2755 units. After the Great Recession, the market bottomed out in 2010, at 962 deliveries, and has since recovered somewhat to where starting in 2013, the industry has been delivering 1200 - 1300 piston planes per year. This isn't an entirely apples to apples comparison, as starting in 2013 Tecnam joined GAMA, and they have been building 180-190 airplanes per year. Tecnam's pre-2013 sales aren't included in GAMA's totals, so the comparable figure for recent deliveries is closer to 1100 per year. That's a global figure, around two thirds of those airplanes wind up in the United States, the rest mostly go to Europe, Canada, and Australia.
In that peak year, Cessna delivered 865 piston singles, and no twins. That's 31% of the global total. In 2018, Cessna delivered 193 piston airplanes, which is 17% of the global total. 193 airplanes is the fewest piston engines they have delivered in that time period, fewer than any year in the depths of the Great Recession. My best guess is that Cessna could sell more Skyhawks, Skylanes, and Turbo Stationairs than they are currently building, but have no desire to. My suspicion is that the reason they are building piston singles at all is to keep their production facility open until the two new turbine airplanes they have announced are ready for sale, and as soon as that production capability is needed for those airplanes, the piston singles go out of production. I have no actual knowledge, of course, and could be totally wrong.
In 2005, Piper delivered fewer than 24% as many piston airplanes as did Cessna, while in 2018 they produced 80% as many. So far in 2018, Cessna has delivered 121 piston singles, where Piper has produced 116 Archers, 16 M350s, and 25 Seminoles. At that rate, Cessna will deliver 160 piston airplanes this year, and Piper will outproduce them handily. Maybe Cessna is planning on building piston airplanes indefinitely, but it sure doesn't look like that to me.