I expected a bitter reply like this at some point. Fear not, I do have some thoughts for you.

• Sucking at design: I never even remotely suggested that if you don't travel, you'll suck at design. I am simply encouraging designers to get out there, interact with different people, and apply that back to their work. There are infinite ways to do this. You won't suck at design if you don't travel. You'll suck at design if you approach every experience or suggestion with negativity, anger, and bitterness. You'll suck at design if you focus on being outraged and upset that others are doing something that you aren't, rather than using it as inspiration and motivation to better yourself or your work.
• Expensive and privileged: This is precisely why I suggested re-thinking vacation time as a first step. It's simply a repurposing of existing resources. You don't have to go to a different country. Just getting out in your community and spending time with different people could be immensely valuable. The concepts that I introduced could be applied at any place, with any budget, in any time frame. But make no mistake, I agree with you that travelling and living abroad is a privilege. A privilege that I worked very hard for and absolutely earned, and a privilege that I encourage you and other designers to work for as well. Whether or not it has to be expensive is a completely different thing. I have traveled and lived with many people who came from nothing, and to this day have nothing. They've just elected a certain lifestyle and arranged their priorities in a way that places a high importance on travel.

Either travel, or don't. It's completely up to you and I was just making a humble and friendly suggestion, sharing a point of view. But don't inflict your bitterness on people who choose to work and live differently than you.