There's quite a few third party boards that are far better than the Raspberry Pi 4. I found the Rpi4 quite disappointing, especially the half-supported GPU and the lack of AES/crypto extensions in the ARM64 chip. Only ARM64 chip I've ever seen that lacks those.
The target market for the Raspberry Pi foundation is education. They get cheap boards into the hands of people everywhere and provide plenty of documentation to get them started.
Raspberry Pi has the biggest community, and therefore it’s the best choice for anyone looking to get started.
If you’re the type of person who needs very specific features like AES acceleration, then you don’t want to invest in a board aimed at education markets anyway.
The Raspberry Pi 4 is actually very performant due to the Cortex-A72 cores, which are not common on other SBCs at low price points. It’s actually an incredible performance value in the space, even if it doesn’t fit everyone’s exact situational requirements.
In my opinion, Raspberry Pi's main problem has to do with using SD cards, which are prone to errors and corruption. It's a kind of media storage that works best if it operates more statically--for instance, you read some photos on your camera, remove a few, take some new ones... and that's it for the day. They are not intended to undergo a large number of read/write cycles on a regular basis, and that's what the Raspberry Pi makes them do, using them to run its OS.