It needs to be noted that the rate at which the PLAAF is modernizing its fleet will not be sustained forever and will reach a plateau.
All growth will eventually reach a plateau depending on how one measures it.
For example, going from say, 10 to 200 AESA equipped fighters in the space of three years in terms of "percentage increase" is a 2000% increase in AESA equipped fighters.
But hypothetically going from 200 to 500 AESA fighters in the next three years would "only" be a 250% increase in AESA equipped fighters even though in those three years the absolute amount of AESA equipped fighters added will increase compared to the previous three years.
That plateau, given the comparative budgets and industrial capacities of China and the United States, is bound to be much more numerically & technologically conservative compared to that of the USN/USAF. What you're witnessing now is just the PLAAF attempting to catch up, and when it finally reaches what the PLA brass deems acceptable, it will still be far inferior to the USN's aircraft in terms of both quantity and quality.
I would be interested to know what you think the PLAAF's level of "acceptable" would be considering the PLA's overall modernization trajectory is one that will be evolving as long as the nation's economic health and technology base keeps evolving.
I don't expect to see a significant portion of older J-11B/J-10A/B to be retrofitted with AESA radars, especially airframes from earlier batches. As these aircraft approach the end of their service life, it becomes less of an advantage to have these expensive MLUs with higher-end avionics that would better be used on a new airframe. The further delayed this anticipated MLU program is, the less of a quantity of J-11B/J-10A/B that will be converted.
Considering the vast majority of J-11Bs and J-10A/Bs only entered service within the last ten years, I think we are hardly in a rush to start calling full time as to whether they will be upgraded or not. Maybe in another five or ten years if there is still no indications of an MLU being done I would agree with you.
Of course I'm not in denial of the PLAAF's rapid transformation into a modern air power through these means. But make no mistake that they have a long, long way to go before they can stand toe-to-toe with its most urgent opponent, and that even if they wanted to match the USN, it is doubtful that they could.
In terms of military aerospace technology I think the PLA's advancements over the last decade has exceeded expectations in almost every domain.
In terms of military capability and the balance of strategic air power in the region I think if I were the PLA I would much prefer to be where things are in 2018 rather than 2008 or 1998.
And in terms of the PLA's military aviation capability to fight a regional high intensity war in a multi-domain manner, the gap in military capability has shrunk even more dramatically.
Wholesale numerical comparisons of capability of course means the USAF and USN would take the no.1 and no.2 spots (or vice versa), but the pace at which the PLA has climbed up the ranks from two decades ago to now is unprecedented.