Because it will be provided by Amtrak... and that way Amtrak provides the true terminus in Vancouver.
Imagine if you were to take a train to Seattle, but it dropped you off in Everett and gave you directions to the LRT. Not good business.
Skytrain isn't run by Amtrak.
Case in Point, you can book a ticket from Vancouver to San Francisco, and it will involve a bus from Vancouver to Seattle (As the night train doesn't sync with the Coast Starlight.)
If anyone's interested, check out page 6 of this PDF:
http://www.wsdot.wa.gov/rail/amtrakp...s/chapter3.pdf
The improvements between Bellingham and Vancouver are supposed to be:
Vancouver <---> Bellingham
today 2008* 2023
1:48 1:39 0:50
(original midpoint... but is now undefined due to funding)
Overall Trip Time:
Vancouver <---> Seattle
today 2008 2023
3:55 3:25 2:37
That goes to show you where the bottleneck is. BC. Overall improvement is supposed to Shave 1:18 off the time from Seattle to Vancouver. Bellingham to Vancouver is 0:58 of that... or 75% of the time savings.
Imagine getting to Downtown Seattle from Downtown Vancouver in 2:37.
A CAR takes 2:34 according to Google Maps(with no Traffic and no border wait...).
If you could pre-check customs at the Vancouver terminus it would be MUCH faster than driving.