Why don't piston engines require as heat resistant materials as jet engines?
Lubrication.
The low wear of piston engines is due to an oil film between piston rings and liner, so both never get into immediate contact. This perfectly thin oil film left on the liner bore by the oil control ring will flash off if temperatures exceed 180° - 200°C, and the piston rings will scuff. This need for lubrication is the weak link which makes improving heat resistance for piston engine materials redundant.
Lubrication in turn requires sufficient cooling which is possible because combustion in reciprocating engines is a discontinuous process with only the end of one and the beginning of the next stroke producing compression and combustion heat while the others allow to cool down the cylinder head and walls.
Contrast this to jet engines. Continous combustion produces much higher thermal loads so any attempt at sealing the compressor and turbine disks against the outer casing is futile. Only the development of heat-resistant alloys has made this possible: Look at how the improving materials allowed increasing compression ratios. Modern turbofan engines reach compression ratios of up to 50:1 while diesels are stuck at around 20:1 and gasoline engines at around 10:1. Aviation pistons with superchargers raise that to levels similar to modern turbofans: The Wright R-3350 turbo-compound engine supercharger increased pressure by 6.5:1 with the pistons compressing air again by 6.85:1 for a total of 45:1. The highest compression ratios were achieved with super- or turbocharged diesels. The Jumo 205D supercharger achieved a compression ratio of 8.85:1 and the engine another 17:1 for a total of 150:1, but in all cases needing intercoolers to keep air temperature low enough and using waste gates or staged chargers to only reach the top compression ratios close to their critical altitude!
Since decades we can read about &quot;adiabatic engines&quot;, piston engines using heat-resistant ceramics and doing away with the whole cooling system. Their implementation has so far not happened because the wear between piston and liner has been unacceptable (among a host of other problems, like manufacturing cost and brittleness).