>>37940087Gen 2 upped the ways to make shit rare, item requirements for trade evos, swarms that required specific phone numbers, hiding them away in weird tucked away places, happiness, etc, this was in order to keep shit from being easy to find and to encourage exploration and to get word of mouth going with kids cooperating to help each other. That's why a lot of the newer shit seems so inaccessible.
Does it suck that I cannot use Houndour until the late game? Sure, but nowadays I can get around the problem by just injecting and back then you could get past this issue by asking a friend who was ahead of you to trade you one.
tl;dr: The game wasn't designed with every monster being accessible in mind and you had to be there to get it.