I can support your statements based on my own experience.Selling premium on individual stocks requires stock picking skills and market timing skills. Doing it relentlessly and mindlessly will not work in the long run. Larry McMillan has said that selling covered calls this way works out to a T-bill-like rate of return. My few backtests, although not extensive, indicate this view is correct. He suggests using some simple technical analysis to avoid bad times and bad stocks (stock above the 20-day MA is the example he used, although it may not be the best approach).
Mechanically selling covered calls in 2013 resulted in very poor returns (compared to buy and hold). For six months I sold hundreds of covered calls, lost my stock holdings and then had to buy them back. To add insult to injury, I had to pay capital gain tax. I now do covered only on occasions and it is profitable that way.