Wonderful explanation, Tecumseh. You very clearly explained the reasoning behind and the issues that arise from the Priority cost of metatypes.
In pure numbers, a Dwarf sounds like a serious boost, but an Elf boosts more universal attributes. BOD and STR aren't the most useful attributes in SR5, (especially STR, BOD has good benefit, but it no longer restricts your maximum Armor, so a good piece of armor can make up for what would have been a crippling weakness in SR4A) while AGI and CHA benefit significantly more skills, and are attributes people more often want to maximize, meaning the increased capacity is a big deal.
As well, BOD and STR are less useful outside of specific archetypes. STR is almost useless outside of melee, unless you're relying on constant Full Auto on Heavy Weapons. BOD is useful to all archetypes. For an Elf, CHA is ignorable for a lot of archetypes (everything but Magician and Face can afford to have it very low), but AGI is useful to almost every archetype (everyone should be able to fire a gun).
It then looks closer to this...
Elf +1 Attribute Points for 1 Priority Points
Ork +3 Attribute Points for 2 Priority Points
Dwarf +3 Attribute Points for 2 Priority Points
Troll +4 Attribute Points for 3 Priority Points
As you can see, it starts to really cost a lot for little benefit in this regard. Especially when you compare how much those Priority Points would get you if you bought Attributes. 1 Priority Point in Attributes is either +2 Attribute Points of +4, depending on how many you've spent on it. The 3 Priority Points spent on Troll would get you at least 8 Attribute Points, max 10. The 2 Priority Points spent on Dwarf or Ork gives at least 4 Attribute Points, but up to 8 if you were already at C Attributes.
As such, if you play an archetype where STR isn't useful (AKA, the majority outside of Close Combat), Ork, Dwarf, and Troll are all mechanically a loss. Sure, you could decide that making a Dwarf decker use melee makes it not worthless, but that is just the Sunk Cost Fallacy at work.