Is the goal of Pokemon to literally "catch em all"?

Question

Okee
So I have defeated the E4 a looong time ago
I've gotten all the legendaries (I think)
I'm really not sure what I'm supposed to be doing. Is the goal really to "catch em all"?
And if so, HOW? Can't you only get some as starters?
Thanks!
BTW I'm playing Pearl, Yellow, and Crystal.

Answer 1

Well personally I never cared about catching all the Pokemon but in order to truly complete the game you have to fill the pokedex. I think it's stupid because they did it so that you have to trade with freinds in order to see all the Pokemon to complete your dex, which I find stupid because if none of your freinds play Pokemon (And that'd be me) then you are basically screwed, but yeah. You can't get them all without trading or hacking, and yes, in order to truly complete the game the pokedex must be completely filled.

Answer 2

There are numerous things to do after defeating the E4. Catching all is definitely one of the biggest and most difficult challenges, but there is a sort of "success meter" in the form of Trainer Stars. Completing this is extremely time consuming and involves almost every major achievement in the game except actually batteling other players. They range from completing all Contests, Battle Tower and etc. These Stars is is different in every game.
You will have to trade or migrate starters and some other Pokemon to get all of them. The GTS (Global Trade Station) is a easy way to get them.
But if you want to do something else:

• Defeat the Battle Tower/ Subway/ Frontier.
• Complete the Pokathlon/ Pokemon Musical/ Pokestar Studios.
• Battle other players over Wi-fi.

Source: http://bulbapedia.bulbagarden.net/wiki/Trainer_stars