Delta Comfort+ vs Premium Select price: why is the gap so big?

Yes, that is pretty normal. A few reasons:

1. Different products. Comfort+ is extra legroom in the main cabin, while Premium Select is a separate premium economy cabin with a better seat and service.
2. Limited seats. Premium Select cabins are small, so fewer seats means higher prices, especially on popular dates.
3. Route and timing. Long-haul and last-minute fares are usually more expensive.
4. Demand changes daily. Prices can move up or down, so it is worth checking a few times.

Tips to save:

• Compare prices at booking and again in Manage Trip.
• Be flexible with dates if you can.
• Check whether your SkyMiles status gives upgrade options.

If you only need legroom, Comfort+ is the better value. If you need sleep on a long flight, the extra cost of Premium Select may be worth it. More on the Delta Comfort+ price is explained here.