(...) it's perfectly legal to make a clone, especially one that's completely different in terms of implementation. Even using FTDI's VID:PID is fine because it's required for interoperability. The only thing that's not is marking it with the FTDI name, and that's not something the driver can determine. In the previous long thread there was mention of COB clones, which are completely unmarked, and this one. Perhaps you work for FTDI...? ![Roll Eyes ::)](https://www.eevblog.com/forum/Smileys/default/rolleyes.gif)
That's exactly what I think too. If the guys making "second source" FT232s (to use rs20's term!) hadn't branded them FTDI FT232RL, then they would be in the clear with possibly a better product and since they have a lower price, they'd have a huge demand for their chips.
It is possibly just a coincidence, but the CH340G chips appeared just around the time of FTDI Gate 1.0. I wonder if the manufacturer of the "second source" FT232 and CH are related. Neverthless, the CH340G chips possibly are taking a lot of market share of the FT232RL, since it is cheaper and as easy to implement (although it requires external crystal, which the FTDI part doesn't). I believe 99% of the Arduino clones are being shipped with the CH340G nowadays.
And, for the FTDI fanboys out there, WCH (the manufacturer of the CH340G) also has working drivers (for Win, Linux and Mac), so that isn't a big deal. It's not like creating serial drivers for Windows requires an investment of millions of dollars.