They decimated their farm system. Absolutely tore it to shreds. There were no half measures taken.
The kind of talent they traded away is not the kind of talent that can rebuilt in even two years. And the Padres are fully aware of that. Sure, they can draft and develop nice players over the next couple of years but what they traded away took over a half decade to build.
And good for them! I'm not saying they made a mistake, baseball teams should sometimes do crazy ****, it brings energy to the sport... but it's not my preferred method of franchise management.