I agree that travel documents and similar identity documents should have an expiration date, to force an update to newer technology or standards, catch any changes in underlying personal data, etc. Whether 10 or 20 years can be debated.

The current OCI card is actually machine-readable with the ICAO standard format. If you take a look at that, you will see that it actually has an expiration date, it's not really the "lifetime" validity that the text on the document claims. The expiration date is the day before your 100th birthday.