Microsoft did that for a purpose. The flightsim world was calling for a sim that could be added to, i.e. more potential for scenery enhancements for scenery developers.
Microsoft was asked to exlude some gates and other scenery features in parts of the sim so that developers could upload enhancements to the internet to add those missing gates, and have downloads.
Basically it's a deal between the freeware FS designers and Microsoft to create an interesting sim that is funn to build scenery for. That's all.
FS2000 had nearly everything, so not alot of scenery was put out for it, hence less interest in FS dowloads. You'll see the fun of FS98 come back to FS2002 in the form of addons.
Wait about a month and you'll see a ton of addon sceneries on Flightsim.com that will add gates and everything else to the sim. It's made to be improved upon.
That's why it's so cool!!