It's not so much to do with Oregon it is to do with the company and the industry. Symantec is a slowly wasting away. They peaked in late 2004 and have been in decline ever since. 

They are not the only multi national company slowly exiting the city, but not just the city they are leaving the country. Levis just down the street will probably have relocated all their jobs from the Eugene building to overseas in the next 5 years. 

It's not Eugene it's just business. Same reason These companies came here from California in the first place is the same reason they are leaving. Cheaper labor. India will perform the same jobs (granted at a much lower quality) but at a tenth of the cost.