So... why aren't there archetypes that give you an eidolon or phantom?

[JiCi]

There are plenty of archetypes that grant animal companions and familiars outside of druids and wizards, but there's like no non-summoner/non-spiritualist archetype that grants an actual eidolon or phantom.

I'm not talking about getting evolutions, but "replacing a familiar with an eidolon" for a golem-focused spellcaster or "replacing a companion with a phantom" for an ancestral spirit-focused ranger or hunter.

[Belafon]

The druid Elemental Ally and Planar Extremist archetypes get eidolons.

Cavalier (ghost rider) and Druid (death druid) both get phantoms.

As for "why aren't there more?" it's primarily because it's actually quite difficult to disentangle the eidolon from summoner class features or phantom from the spiritualist. It's not like a familiar which is an individual class feature that says "you get a familiar, see the rules for familiars." If you want to give an archetype a phantom you have to decide which of the spiritualist class features you want to give them. Phantom, sure. What about bonded manifestation? Greater spiritual influence? What are the normal class features we would need to remove to balance it out?

And of course a familiar and an eidolon are nowhere near equivalent in power level. Taking away other wizard class features to get the eidolon (or giving him a weaker eidolon) is not an easy decision.

[glass]

There is also that animal companions and familiars have been in the game since the CRB, whereas eidolons and (especially) phantoms are much more recent. So there has been a lot more time to publish archetypes for the former than the latter.

_
glass.

[JiCi]

glass wrote:

There is also that animal companions and familiars have been in the game since the CRB, whereas eidolons and (especially) phantoms are much more recent. So there has been a lot more time to publish archetypes for the former than the latter.

_
glass.

Eidolons were introduced in 2010... and we got nothing concrete up to 2018...

[avr]

JiCi wrote:

Eidolons were introduced in 2010... and we got nothing concrete up to 2018...

Just guessing, but there was some furore about the original summoner's eidolon being overpowered. Adding more places for the eidolon to appear might have been off limits until editorial control was released as PF2 was designed.

[David knott 242]

Belafon wrote:

The druid Elemental Ally and Planar Extremist archetypes get eidolons.

One interesting point is that the eidolons of both of these archetypes are unchained eidolons, so they weren't possible until Pathfinder Unchained was published in 2015. And Occult Adventures was published a few months later.

So there was a period of about five years after the publication of the Advanced Player's Guide in 2010 during which there really wasn't considered to be any design space to grant an eidolon to any other class.