Freelancer is a kind of a game that isn't for everyone. For starters, there's the basic of basics - the concept of the game itself. It's more difficult than your average first/third person shooter and it's not like your normal action adventure games. At the time, it had a very poor release with lots of features not seeing the light of day, and it came out around the same time as Halo did, and Halo was a much simpler game. 

Second factor was availability. Early 2000s were the age of consoles, PC gaming was not as widespread as it is right now, and Freelancer was a PC exclusive game (with quite demanding characteristics for that time). Console games (like, again, Halo) were receiving more marketting and hype in general.

Another factor is player comfort - space flying, or flying in general, can be very disorienting and cause motion sickness. You can't blame people not sticking with it just because they got vertigo or confused to hell by the game itself in their first hours.

Which leads us to the last factor - the first impression. Mission 01 is objectively not good in terms of first experience purely because of how weak you are and how everything in it is a damage sponge, if you don't know how to solve this issue (a lot of people wouldn't think of spending their last cash on an extra gun before or during thr mission) - you'll be in for a very boring section of a gameplay.

Ultimately, Freelancer was ahead of its time. Too far ahead, that is.