Over the past two years I've spent less than half that time in Thailand. The rest in Vietnam and Malaysia. Each time i leave Thailand I'm away for 3 months. I know a lot of people bounce in and out. I'm not one of those people. My Facebook profile doesn't say i live in Chiang Mai. I've tagged CM in some Instagram posts, so maybe that's what you've seen.
One more thing. Just remembered. I didn't have a flight onward booked. Not smart I know. I had flights booked the last two visits and they didn't ask. I encouraged the official to look at my near full passport and see that I've never overstayed anywhere, and got away with that.
I spend 3-6 months away from Thailand at a time. I've got about 4 60 visas in my passport too. They will ask you eventually. This was my first time. Tourist numbers are down. The Chinese numbers have dropped significantly. The Thai government just launched a drive to turn things around.
Why I spend so much time in Thailand? I said "because i love Thailand, have Thai friends, love playing pool in Chiang Mai". She was friendly and apologetic. That's when she said she had to ask because of the 6 entries (not back-to-back)
The immigration officials are directed to question tourists coming in after 6 30day stamps. Even not back to back. She told me this when i came in this time. And they wonder why their tourist numbers are down.