Fair enough. Could have been worded better especially given
1) US does have GaN based satellites already
2) The whole GaN based satellite in non-GEO orbit is really a decade (singular) long thing rather than a "decades" thing? As such, the struggle to get a GaN based GEO satellite can only be a decade long thing rather than "decades"?
Anyway, just nitpicking.
You are still incorrectly reading/interpreting the article. The 'decades' referred to how long US has been trying to place a useful SAR satellite in GEO. GaN is the enabling technology that allowed China to succeed in GEO.
I suspect most people read the article the way it was intended. Instead of suggesting the article be worded better, perhaps you should self-reflect and improve your own inference and reading comprehension first. The article is written for typical adults.