Which didn’t include Uranus or Neptune. If you read that article, it was only the planets you can see without a telescope: i.e. Mercury Venus, (Earth), Mars, Jupiter and Saturn. Still reasonably uncommon though, especially in that exact order.

Seeing any three planets in the same part of the sky is trivial. Happens all the time..

But seeing seven (plus earth) is exceptionally uncommon. It will happen again in 2040 and after that 2854.

Neptune and Uranus have the longest orbits (165 and 84 earth years respectively) so most of the time they’re not in sync AND you’ve got to wait for the other giants and inner planets to be on the same side of the sun too, so you can understand the rarity.

A parade is not the same as an alignment by the way. An alignment is when the planets (from earth’s perspective) line up within a narrowly defined margin of one another. If that margin is one degree of arc for example, you could expect all 8 planets to align once every 13.4 trillion years. Which is to say, never, because that’s 1000x the current age of the entire universe. On the plus side, the sun will become a red giant, engulfing Mercury and Venus within that time, meaning fewer planets and thus slightly higher chances of alignment. Then again the earth will be consumed too, so, you know, c'est la mort.