all that for a 22 000 miles car ? must have been pretty rough 22 000 miles...
Take a piece of lightly-painted (maybe not on all sides) sheet metal and place it in your backyard for 50 years. Will it look new? Not likely, but the answer is highly dependent on where your backyard is. My car is wearing its original non-galvanised chassis, but it spent the first 30 years in the California desert with only enough moisture to acquire black widow spider nests. Then it did some time in Washington State, and for the last 15 or so it's lived in my garage west of Boston. Prior to being coated with POR-15, it had acquired minor surface rust that is present on other exposed metal areas of the car and pitting to most of the chrome bits.
If it had spent 50 years in a climate-controlled museum, it would likely look nicer. 50 years in my backyard with occasional local street usage, I would expect a highly perforated chassis.
Time doesn't age a car as much as heavy usage and exposure to the elements, but it isn't kind either, and 50 years is a lot of time. The Lotus chassis is certainly not made to last forever. Nor are rubber components, and plastic goes brittle.