Ideally a car will loose/burn less than a quart every 2-3,000 miles. Most do that good, but some don’t. It is dumb luck. If it starts consuming more without reason (like long hot trips etc.) then you may have a problem. It may well be burning it and if it does not burn too much you will not see any smoke and it will not cause problems. When it starts burning too much you can damage the converters and/or start seeing smoke.
BTW evaporation rates would be measured in thousands of years.