You don't buy RTCs. You buy a big SoC with a 5000 page datasheet, of which 3-10 pages are the RTC, and you take what they give you. There is no room for the RTC

You don't buy RTCs. You buy a big SoC with a 5000 page datasheet, of which 3-10 pages are the RTC, and you take what they give you. There is no room for the RTC type/design to be part of the part selection process for a SoC, which is why they can be vaguely crappy and nobody cares or can do anything about it. Edit: it's a power management IC for a SoC, not the SoC itself, but you often don't get much choice of those either since SoCs tend to be designed to pair with a specific PMIC. Whether the RTC is in the SoC or PMIC (or both) depends on the design.