2014 GL450

I purchased a used GL 450 with 160K miles about a year ago. Excellent condition. Car fax indicates one owner with regular shop maintenance and no accidents. However, 3 months after purchase, driver side air suspension went out. Had it replaced. Two days later, the passenger side air suspension went out. Two months after that, a plastic coolant nozzle (behind the firewall) broke. Replaced that. One month later, plastic radiator assembly broke. Replaced that. One month later, AC refrigerant leak in plastic nozzle (behind firewall) found. Replaced that. Two days later, driving along and AC fan suddenly stops. Compressor engages, switch working inside, but no fan. Mechanic tells me that most of the connections in this model are plastic and prone to age-related failure after 100K miles and that is why people sell or trade Mercedes when 100K rolls up. I have a 2000 C230 Kompressor with 200K that I have never had a major mechanical problem. Mechanic says Mercedes wasn't using so much plastic back then. I guess my question is... Is this normal or did I get a lemon, or is something fishy going on with the mechanic? The coincidences are piling up. Thanks so much.

SK