I can write fast because I've been writing online for so long. Most short posts take about ten minutes, longer form stuff usually takes one or two hours.
I also deliberately lower my standards for blogging - I often skip conclusions, and I'll publish a piece when I'm still not happy with it (provided I've satisfied myself with the fact checking side of things - I won't dash something out if I'm not certain it's true, at least to the best of my ability.)
I'm hoping to improve my overall balance a lot for 2025. Deliberately ending my at least one post a day blogging streak is part of that: https://simonwillison.net/2025/Jan/2/ending-a-year-long-post...