Well it depends on what we call "long term". I imagine China won't sustain a 3 unit/year destroyer production rate over the "long term" if we consider that to be 20+ years, but I can imagine them sustaining it over like 10+ years or something (just throwing a number out there).
I see their past and present and near term future naval procurement as being a case of modernization+expansion, where their goal is to both rapidly modernize their capabilities as well as to expand the capacity of those modern capabilities. Eventually I think they will modernize and expand to a "critical mass" level where they will be satisfied with the extent of their capabilities in being able to achieve their core strategic missions to an acceptable degree of risk, whereupon they will move from rapid modernization and expansion, to a more steady pace of modernization and sustainment or at most a more steady rate of expansion.
So IMO what we've seen over the last decade or so was the first phase/early part of modernization+expansion where they produced a small to medium number of capable and competitive but not world leading capabilities to provide an interim/immediate capability and seed/training for future assets, while also heavily investing in R&D and infrastructure to allow them to build future more advanced and more complex ships in greater numbers.
Now going forwards I think we may see a more robust, synchronized push of modernization+expansion (building on the R&D and infrastructure investments of the previous phase) to reach the "critical mass" of modernization+capacity in the medium term future.
I agree with your general characterisation of past, present, and future, however I believe that if China continues to produce 2 destroyers and 2 frigates per year, such rate is not only sufficient to deliver a fleet comparable to USN in the long-term, but is capable of delivering significant expansion and modernisation over the medium-term as well, i.e. your "10+ years" -- let us say to 2030.
If China commissions 2 destroyers and 2 frigates each year between 2017 and 2030 that equates to 28 of each type. The 28 destroyers will replace 8-11 existing destroyers (051s, 052s, maybe 051B and 956As), therefore increasing total destroyer numbers by 17-20 over the period. The 28 frigates will replace 13-19 existing frigates (053H1s, 053H2, 053H1Gs, maybe earlier 053H3s), therefore increasing total frigate numbers by 9-15 over the period. Thus, even at the more modest level I suggest, the total number of major surface combatants increases from the current number of 76 ships to 102-111 over the period. Improvements in tonnage and technology terms will, of course, be much greater.
It is certainly possible for China to embark upon a more rapid (and less sustainable) path of expansion by producing 5-6 major combatants each year over the 2020s rather than 4, but beyond producing the undesirable long-term effects that I mentioned in my previous post, such a path seems incongruent with what we have observed to date in China's approach to military development. China's willingness to reduce military spending growth in line with broader economic performance these past few years suggests to me that PLAN is unlikely to try to rush for a "USN-level Navy" when a more modest schedule will in any case deliver that outcome over time.
but want to say it anyway) one thing is the ability to acquire new warships, another thing is the ability to man the new warships ... irrespective if it's for example PLAN, USN, RN (for which it's known issue Aug 31, 2016) or LOL my favorite Brunei Navy ... I think that's all what I have to say now
