If you need a new Mac, then get it when you need it. Do not wait for the next thing.
When the switch to intel happened, first it was announced. Shortly after that, developers could by a system to developer intel based software. About a year later, users could buy an intel based Mac.
This is the history of the PowerPC to intel transition: https://en.wikipedia.org/wiki/Apple%27s_transition_to_Intel_processors
Even after the intel Macs became available, a lot of software still ran under emulation because either the user was not ready to buy intel copies of the software, or the developers had not released an intel version, or the author had abanded the software and the software was end-of-life (in the case of end-of-life software, it died when Lion 10.7 stopped including PowerPC emulation).
The Motorola 68K series CPU to PowerPC switch included 68K emulation. The PowerPC to intel switch included PowerPC emulation. One can only hope that a switch to ARM will include intel emulation.
But you only have to worry about that IF AND ONLY IF Apple decides to switch to an ARM-based CPU.
Just because some pundits have decided Apple should switch, does not mean they will.
So personally, I would get a new intel based Mac when you need one, and not worry about a switch to ARM until it is actually announced.