CM500 cable modem -- losing connections & grounding

Heya folks...would like to get insight on grounding, in-house wiring, and cable modems here. Currently with Comcast and a CM500, was fine for a few years, now currently dealing with several losses of connectivity a day. I've done the whole capture log cycle and had a Comcast tech at the house already -- I'll post a link to the details on the Comcast forum site below -- but I'd really like to direct attention to the interaction between house electric grounding and the NetGear CM500 on this discussion post. I've seen lots of support posts saying there may be issue with the lines in the house, and I want to start the discussion there. 

Conclusion from the Comcast tech: although my house is a relatively new construction @ 6yrs old, fluctuation from the electric panel is causing the modem to hiccup, with the likely possible cause being a 'patina' if you will on the grounding behind the breaker panel. Suggestion was to get an electrician in to clean and reset the grounding. Can someone explain the impact of this on the cable modem to me?

Let me share a few thoughts...

• Just to get rid of the obvious...there are no splitters on the Comcast line from the street to the coax panel to the modem. We also set up the modem in the garage, where the modem actually saw worse (!?) noise. He confirmed internet signal from the street was fine, and we both looked at the street connection, also fine.
• If this is indeed a real thing, why are cable modems so sensitive to this? Rest of the house is fine...TV runs without interruption, lights don't flicker, FM receiver can maintain a radio signal...don't (or shouldn't) modems have some built-in regulator to handle this kind of thing?
• Maybe I just have the wrong modem? CM500 is fairly basic standard issue, is there another model that takes care of this?
• The tech said that modems use the cable coax for grounding...notice the two prong electric cord vs not having a third prong...which doesn't help maintain it's own grounding, hence greater sensitivity.

If I step back and pause for a moment, I appreciate the amount of black magic where the internet passes through a bunch of wires and in the air for us to watch a movie or buy things from a store...lot of moving parts to help make all happen. And I would just like to maintain a reliable internet connection that doesn't drop a video phone call at bad moments. 

Thanks for your thoughts!

Comcast forum link for scenario, modem logs, etc.

Repeated loss of connectivity | Xfinity Community Forum