From my own experience with Siglent gear I can't imagine that being true or you must only sell Siglent gear which is on the market for at least 3 years OR your customers have extremely low expectations.
To be fair, Siglent hardware isn't bad, actually it's pretty good, at least if it's not rusting
The haptic quality is good, and, some rare issues like the SDG1000 jitter aside, they seem to design the hardware properly, unlike Rigol. I don't imagine that there are many returns because of hardware faults.
The real issue with Siglent is everything software, and since this is, unlike to a hardware fault, something a reseller can't do anything about, I guess many people just patiently wait for the next firmware update.
Juts look at this forum, it's truly amazing how many people are willing to play beta tester for rushed out products. Not just from Siglent.