They can be solved fairly easily, and, unless combined with the other half of their combos (proliferation of counters, Mycosynth Lattice, Wheel of Fortune), dont have a huge impact on the game for more than a couple of turns
Three decades later, Wizards of the Coast releases several hundred new cards every year across Standard sets, Commander products, and Universes Beyond collaborations
Unless you predict the game is going to reach its conclusion by running your opponent out of cards, those cards could have just as easily been on the bottom of your opponent's library and the result would have been the same
The Pokemon 151 set has very valuable cards in the Japanese version
No documentation proves a release before the 1996 TCG launch