Is RISC-V better than ARM?

Not universally. RISC-V's advantage is that it is free and fully customisable, which matters enormously for cost at scale and for custom silicon. ARM still has the more mature software ecosystem and, in many cases, higher peak performance today. For a phone, ARM. For a custom embedded chip where you want to avoid royalties, RISC-V.

Will RISC-V replace ARM and x86?

Unlikely to replace them outright any time soon. The more realistic future is three architectures coexisting, each strong in different segments, with RISC-V steadily taking share at the edges and in AI rather than wiping the others out.

Why can't I buy an x86 chip licence like ARM?

Because x86 is a closed, proprietary architecture controlled by Intel and AMD. There is no licensing programme for outsiders. ARM, by contrast, exists to license its architecture, and RISC-V is free for anyone to use.

What's the easiest way to try RISC-V at home?

A single-board computer like the StarFive VisionFive 2. It runs mainline Linux, costs about the same as a mid-range Raspberry Pi, and gives you a real RISC-V machine to tinker with rather than an emulator.