Wow, you're in an enviable position. Living in Colorado, your trips are probably limited by cold weather part of the year. When we were young, we camped with toddlers; and, with small children, a travel trailer makes camping much easier and more enjoyable than staying in a tent, especially in bad weather. Also, a trailer extends the camping season with heating and air conditioning; and with women and children, it's great always having your own toilet facilities wherever you go.
Personally, if your Airstream is paid for, I'd keep it. You may be able to use it more often by selecting destinations further south when the cold weather comes. It's only a few hours drive on I-25 to great camping in New Mexico and Arizona where the winter daytime temperatures will be 50-65, instead of freezing. Also, all you have to do is get south of the snow-packed roads, and your Airstream can be a warm retreat for winter fun. We have camped (in Denver) in temperatures down to the low-teens.
Looking ahead, you won't always have children at home (hopefully); and your Airstream could be part of your retirement plans. With routine maintenance, your trailer will still be in good condition; and you won't be shopping for a new one (yikes, what will that cost in 20-30 years?), or looking at fixing and refurbishing a trailer that some previous owner has "customized".
So, if you're in a financial position to keep it, and your family likes camping, this could be a no-brainer. Otherwise, you'd be wise to sell it ASAP; as with time, it will only decrease in value and slowly rot into the ground (the destiny of all RVs and boats).
One thing to consider is resale value. After five years, your Airstream could be worth considerably less than you think, which may make the decision to keep it easier. (It may be worth more to you to keep it, than to sell it at what seems like a huge loss.) However, years ago, we stored a five-year-old van when I got laid off, thinking we would return it to service as soon as I found a new job. Unfortunately, it sat rotting into the ground for 20 years; and I ended up selling it for $300. That would be a shameful outcome for your travel trailer, even though a 25-year-old Airstream is worth a lot more than 25-year-old customized passenger van.
Just some things to consider...
By the way, we just retired, our kids are over 40, and our granddaughters now prefer strolling the mall with their friends to road trips with their grandparents. So, we're headed out to "see the USA..."; be back -- whenever...