For Shaw in BC:
http://www.shaw.ca/personal/television/channel-listings/
Sportsnet 1 HD and TSN2 HD both in HD Basic package. So, you get two TSN channels, two Sportsnet channels in the same HD tier. 360 is in their HD(sports plus) tier.
On Bell, TSN 2 HD, Sportsnet 1 HD, Sportsnet 360 HD, and all the Regional Sportsnets are on the same tier (Ontario).
http://www.bell.ca/Fibe-TV/Fibe-Channels
On Rogers in Ontario: You get Sportsnet Ontario with basic cable, Sportsnet and TSN with the digital 'plus' package but only Sportsnet in HD, You get all the Sportsnets and TSN and TSN 2 in the extra sports, but only the Sportsnet channels in HD. In order to get the TSN's in HD, you need to shell out an extra $10.
So, in Shaw in BC: If you have TSN and TSN 2 in HD, you should also have Sportsnet Pacific, and Sportsnet 1 in HD as well. Sportsnet 360 HD is in another package. Seems fair.
On Bell in Ontario (and I assume in BC and wherever they are available), if you have TSN and TSN 2 HD, you should also have all the Sportsnets in HD.
On Rogers in Ontario (Rogers may vary more depending on area, don't know): You get all the Sportsnets in HD for $10 cheaper than the package that includes TSN and TSN2 in HD (which also includes all the Sportsnets).
And my current cable provider has all of them on the same HD tier (except for other region sports nets). TSN, TSN2, Sportsnet Ontario, Sportsnet 1, Sportsnet 360 are all included in their basic HD package.
So, your portrayal of the Sportsnet channels being their obscure premium channels compared to TSN2 doesn't hold much water.
Oh, and since it sounds as though you are from Alberta: Shaw Alberta:
http://www.shaw.ca/personal/television/channel-listings/?lregion=AB&lcity=Calgary
Similar to BC. Should be noted the Sportsnet 360 is included in basic cable. HD situation is the same as BC. TSN, TSN2, Sportsnet West, Sportsnet 1 are all HD Basic. Sportsnet 360 is HD Sports (Plus).