We already realized the necessity of finding information amongst the exponentially growing wealth of Web servers (sites).
And Google obviously worked much better than the existing crawler-based search indexes and curated directories.
And lots of people thought a "portal" was a good place to be, if you could manage it.
Funny thing is I recall using Google from the very day I first saw it come across Slashdot -- probably late 1997 -- before they were incorporated even... but I also recall that at some point around 1999 I actually switched back to using AltaVista or something similar for a bit. Because I preferred the search results I got.
It was actually a more competitive situation than people might remember in hindsight.
The big difference is that Google made it through the .com crash filter better than anybody else. That and they kept the good will of their customers by keeping minimal and straightforward and (for a while) ad free.
Plus the no fast no clutter homepage for google compared to how many links can we fit in one screen for the portals
Maybe AltaVista improved after that, which could explain how the parent commenter could go back to it.
The turning point that brought me fulltime to Google from then on (until recently switching to Kagi) was when they started having almost live results. It's hard to remember or imagine but search indices were often days, weeks out of sync for critical things like news, etc and Google was really the first to fix that.