Yes, this is true. Don't buy an iPhone/iPad/Mac. I've been hacking for 30+ years, I like that Apple has locked down the phones and the Mac is not locked other than Apple locking their OS. It doesn't stop me installing Macports and then the endless array of FOSS that I want.
General purpose computing is slowly evolving, like every other technology before it, to separation of the creation of code from the use of code. Computers and phones are a tool for most people, the act of coding and/or going outside the provided ecosystem is something that the majority of people, for the majority of the time, don't want or, in a lot of cases, need.
Most people don't have shortwave radios anymore, neither are they interested in amateur radio etc. Government regulations have "locked down" the radio ecosystem but maintained the capabilities for those that want to explore radio "hacking". Computing is going the same way.
If you want to hack your own environment, there are perfectly cromulent alternatives. Android and AOSP for phones and tablets, Linux and the *BSDs for general computing.