Making an assumption that you are talking about 2 strokes.
Piston life varies. To an extent on road 2 strokes they are a consumable, but they might be expected to last 20000 miles plus. On others far less. For example an Aprilia RS125 lists checking the rings at 8000km (~5000 miles), and by the time you have got it far enough apart to check them you may as well replace them; and rule of thumb do I do the piston every other set of rings.
If you look at a 2 stroke cylinder you will see very large ports. These will give the rings a hard life, as they tend to expand into the ports and then be pushed back at the edge of the ports. Often the more highly tuned the engine the larger these ports are, giving the rings a harder life. Some things can be done to reduce this (for example, NSR125 has a bridge over the middle of the exhaust port supporting the piston rings, hence 2 smaller ports rather than 1 large port), but these can affect ultimate performance. Further 2 strokes generally run a lubrication system where the oil is passed into the engine with the fuel / air mix, which is likely to provide less perfect lubrication. Further, with the shape of the ports, and the limitations that provides to coolant passages, the barrel is likely to be unevenly cooled, especially as it is just warming up.
Race 2 strokes (either on or off road) might have a far shorter piston life, with far larger ports plus likely to be run at high revs for far more of the life. From memory some Yamaha TZ250s list new rings at 250 miles, new pistons at 500 miles and new cranks at 1000 miles. But on a race bike, performance is the major factor and extra maintenance far less of a concern.
KTM even list the electric 2 stroke oil pump to be replaced on some of their bikes at 80 hours.
Changing pistons is often not that hard. As an amateur for an RS125 I work on the basis of a gentle afternoons work to remove fairings, drain coolant, remove the head and barrel, replace the piston and reassemble
I possibly should point out that in general 2 stroke bike engines do not rev higher compared to 4 stroke bike engines. Highest reving road 2 stroke I have is a Gilera CX125, red lined at 12000rpm. For comparison, some versions of the Honda CBR250RR (a 250cc 4 cylinder engine from the late 1980s) had a red line marked at 19500rpm. Most modern 2 strokes use reed valves which are not that suitable for very high revs, compared to disk valve 2 strokes