Which sentence of mine ever claimed a plane doesn't have A portal?
The one where you went bold and screamy against the idea of taking a portal from one setting to sigil then another portal from sigil to another setting. You are probably, with this question, trying to indicate that OF COURSE, you can do that, but you won't be specifically where you want to be in that setting.
But, ya know what's funny? Traveling through the sky of a setting is multiple times safer than traveling between spheres (far fewer monsters) and since Spelljamming technology is so easily avaiable, they can hop in their flying ship to go from Sarlona to Khorvaire. Which STILL doesn't have them using the Spelljammer to travel between spheres.
No it isn't. It has a lot of portals. Maybe even thousands. There are infinite numbers of prime planes and the outer planes are infinite in size.
Nowhere remotely close to infinite. And I have the 2e Planescape books. Nobody has a good count(countless!), but it's only in the thousands. many of which people don't know about or how to activate.
My gosh! Multiple portals to an infinite plane. That will be sure to get me exactly where I want to go! Except the odds are good that even if I can find the correct portal, and few know where they all go, I won't be able to use it. Simply saying that they exist isn't the same as people knowing about them and/or how to activate them.
And none of this making up problems really makes it any easier to fly between realities, where you must contend with far far more dangerous situations.
I would also say that "thousands" is not "countless". Thousands indicates that they have counted. Sigil has Modrons, they are immortal, tireless and can count in the trillions if that is their purpose. So, I'm going to have to say that "countless" when dealing with immortals means "basically infinite". Maybe not actually infinite, maybe there are dead realities that no one can find a portal to... but if there are no portals to them, then is anyone even looking to go there? How would they know about that reality to try and go there in a ship? Which direction do they fly for how long?
I mean, let's be fair and balanced here. If a crystal sphere is 2,000 years away by Spelljammer ship, no one is going there anyways. Even if they know about it, there is no point.
How is a portal to the sun more dangerous than flying to a planet?
The portal doesn't open into a sun. That's how.
:sigh: What makes you think these portals are permanent? Many, if not most of sigils portals are temporary, showing up god knows where(people) generally don't, and with triggers that people have no idea about. People often go missing because they accidentally trigger a portal that no one knew about and then goes away.
See, words like "Many" or "Most" indicate not all. So, why do I think that some portals are permenant when we are told that some portals aren't permanent? Because in a binary state like that, both things end up being true.