...that "...[e]ach serious collection should imo at least have 1 Rolex".
If one has a lot of watches and if one sees reason to own a Rolex as part of it, I certainly have no quarrel with owning a Rolex if one wants to. But to make a blanket statement...that "each serious collection" must contain one, is hogwash.
I don't have what may qualify, to some or those who traverse these sites, as a "serious collection" (I own 3-4 watches of worth at any point in time). None are a Rolex and I don't feel less worthwhile as a human being just because I don't one. Recently, I did have the opportunity to buy a Rolex -- to fill the spot of "daily sport watch". And, to be honest, two Rolex models (the Yachtmaster and, to lesser degree, the Submariner) made the "finals" in my selection process (one other "finalist" was the Ulysse Nardin Maxi Marine Chronometer).
The winner was the Glashutte Original Sport Evolution Chronometer, with solid steel bracelet. I chose the G.O. because I thought it to be a better made, more unique and more beautiful watch (there is, as always, some subjectivity in these conclusions -- something I happily admit). The factors that tilted it in favor of Glashutte were (a) a solid steel bracelet that absolutely puts the competition to shame, (b) an in-house movement built on-premises at Glashuitte and (c) a presentation (via the sapphire display back) of the movement that was drop-dead beautiful. Throw in the relative rarity of the model versus mass-produced Rolex models, and there you have my choice.
I take nothing away from those Rolex choices, or the Ulysse Nardin, nor do I criticize anybody who were to buy another model than what I chose as their daily sport watch. But the supposition, that one must have a Rolex, is baloney; there is no "watch collection" rule book that says that and if there is, I'd like to see it.