So you are saying that trend lines which border trends cannot be drawn because trends no longer exist? Well, there will always be trends in the markets as long as there are people who can't read them! And just as the cars you mentioned still run on wheels, the market still moves on supply and demand, which creates trends.
Logic has nothing to do with it. Price charts are a study of human behavior which never changes. A horizontal trend line on a stock back in 1927 is no different then it is today. Everything’s tested in historical markets. The past is a pretty good predictor of the future. It’s not perfect. But human beings drive markets, and human beings don’t change their stripes overnight. So to the extent that one can understand the past, there’s a good likelihood you’ll have some insight into the future. – James Simons, Forbes #82 wealthiest. Information moves a lot faster - some have commented on how bullish price trends seem to break down faster these days - considered a result of rapid information flow of our era.
I gain nothing from trying to convince you otherwise and have said all that i'm willing to say on the subject, so by all means continue to use them if you think they work for you.
Yet the example shown is of parallel or horizontal channel ... clearly showing price coming down into and exiting out and down of the channel. In other words clearly a down trend with a channel inside the down trend. Diagonally down (and vice versa) when showing a trend. When showing congestion or range bound trade zone a horizontal line is used. It's really not that hard to grasp.
People who trade for a living are not so much interested in textbook academic discussions but with practical application. Draw them how you feel they do you the most good but I will caution about the need to be right in this field.
And you can call that line a trend line, a treeline or a hemline. Whatever you like. But the fact is that the term exists as a recognized trading tool in TA.
But is it the best tool or logic for trend trading in 2017?? I compare drawing trend lines to playing tennis in the modern day with a wooden racquet. Yes, it works, you'll still be able to hit the ball over the net and win some points but won't win the match against players with a modern racquet and similar or better skill.
Be it good, better or best depends on the ability of the user. And it is but one tool among many. And while your idea is that only modern is best, remember that you can't roast a turkey in a microwave!