As the article offered no background, I'm lost as to what is being discussed. In the last 20 years I've never had the same employer for 10 years, so can someone ELI5 what is being discussed? Thanks in advance!
Traditionally, the period has been ~90 days, which makes it even harder to weigh your tax options and come up with the $$$$ to exercise the options. Since its expensive, and has a short window of execution, the practice has been viewed by many to be unfair. The Stock Options were a part of your compensation - part of the Risk vs Reward balance you choose when you worked for a startup, and now if you don't have thousands of dollars to spare on a gamble - you forfit those options back to the Company.
By extending the period to 10 years, you have the ability plan accordingly, see if the company will eventually exit, and exercise them when the time is right.
If you leave the company, there is a limited window of time to exercise the option. If you don't exercise it, the stock gets returned back to the company.
This post is favoring that window being long and is responding to blog post favoring that window being short.