I worked at ETRADE around the same time and led the migration from Sun to Linux on the software side, switching everything to Apache was once a radical idea. We switched to IBM machines and not HP, a Sun server cost around $250k and the equivalent Linux server was $5k and outperformed the Sun machines. It still was considered risky by CTOs.

During the dotcom boom there was huge competition for ordering Sun machines and it was difficult to get enough, we were competeting with eBay to get our hands on machines.

During the crash, we went back to eBay as a seller and couldn't off load all the old Sun machines.

Here's an article from the time: https://www.baselinemag.com/c/a/Projects-Enterprise-Planning...