In response to the OP of HoroTraveller..
Caliber 240 which powers the 5110 ( and the subsequent 5130 and 5230 as well) uses Silinvar ( the abbreviation for Silicon Invariable) as part of the escape wheel ( spiromax balance).
This iteration was from 2005 and to that extent you are indeed right in saying that your 5110 from 2000 did not have silicon.
Same holds true for Cal 315 ( silicon escape wheel) as well as Cal 324S ( pulsomax - silicon based escapement and lever) and other iterations which use Silicon.
Patek indeed makes robust watches and relies on base calibers developed decades ago, but which undergo incremental improvements over time ( similar to Rolex). Caliber 240 was born in 1977 and still powers the maximum number of automatic watches within the Patek offerings, including the worldtime, perpetual calendars etc. Caliber 324 which powers many annual calendars has been around since 2004 ( and here again based on cal 315- a rather old workhorse known to have a well documented sticky-date wheel problem)
Caliber 215 is a tiny caliber ( 21.9mm) and modest in terms of construction. Launched in 1974 the caliber perhaps can speak of minor improvements and is continued to be used in cases as large as 37mm ( such as 5196 and 5134). The tiny size and modest finish are perhaps the reasons that Patek has been reluctant to have a sapphire case back.
Thus for long the Patek calibers have plodded along gently without introduction of truly new base calibers for several decades.
I had also pointed out that Patek did not have its own chronograph caliber until A.Lange & Sohne kicked up a fright amongst the Swiss trinity with their Datograph and compelled brands like Patek to frantically try and catch up in 2010 finally.
On other technical shortcomings, I pointed out to the absence of hacking seconds in any of the Patek calibers until the launch of model 5235
Patek is yet to produce an instantaneous calendar change mechanism in their calibers powering the annual and perpetual calendars.
Patek is yet to produce a GMT watch that has an independent second timezone setting ( to the minute for all of the 37 timezones). All Patek dual time / world time watches are based in 1-hour increments only for the hometime.
Patek is yet to produce a real dive watch. The Nautilus which is the flagship sports watch carries a 120m WR.
My intent is not to run down Patek, but to point out that the technical leadership that Patek had displayed in the distant past and even as of 1996 when they launched the first ever annual calendar has been less and less visible and the Brand has been happy to milk its past glory. If “finishing” also becomes a lesser priority at Patek, I am afraid that the market may not be too kind or indulgent for long.
I would be delighted with more initiatives on the lines of 5235, 5170 and 5212A where collectors can truly feel fulfilled.
And hopefully Patek will devote greater attention to finishing.