He just made Blinding Lights the longest charting song on the Hot 100 of all-time at 90 weeks, ending the week of September 11th, 2021 (last week...). He's still the most relevant producer of the last 20 years. His work with Ariana Grande is fire (Into You, Focus, Break Up With Your Boyfriend, I'm Bored, ...)
Though, I understand Taylor not wanting to pay him just for this insignificant job and TBH i don't think Max Martin has time for this...
Let's hope he'll work with Britney on her REAL comeback album. We need him.