Only about 7500 or so Green Cards are issued every year to Indians in each employment based category (capped due to the per-country cap that's applied to India, China, Mexico) in each of the few employment based categories. The number of people who have applied for these categories in the last 10-15 years is much more than 7500 a year, typically almost 10x, so the line moves at a glacial pace, usually moving a month every year.
The line for EB-2 and EB-3 (where most Indians are) is currently servicing those who applied in Summer 2012. So if your colleague got in the line in say Summer 2015, that's 36 months away. At the current pace it could easily be 20-40 years before their turn comes.
Also remember that there was a massive tech boom in the 2014 to 2019 period, so a LOT more people applied during that time so the movement of the line will slow down even beyond the current 1 month per year rate. If your colleagues applied in 2016 or beyond they are unlikely to get it in their lifetime unless the per-country caps are removed.
Finally, you'll sometimes hear the word "retrogression". That refers to the line actually moving "back". This happens because the date that the USCIS announces as the "pointer" to who is being issued cards is an estimate based on the recent green card issue rate.
Sometimes it can move back if they had to issue more green cards than they expected to (since people can apply for spouse and kids together when their turn comes).
Sometimes it moves forward faster if the number of people they expected to apply for the final processing stage turns out lower than their estimation.