Re: Macs typically have a longer usable life than Windows PCs ...
These days? I'm not so sure. Apple's hardware is pretty reliable, but the fact that modern Macs are increasingly soldered together and unupgradable means that "planned obsolescence" is increasingly built into them.
To be fair, with 4 Thundebolt 3 ports you have upgrade paths for GPU and fast storage covered. This was not possible before in the older generations that had Firewire 800 and USB 2. You need only worry about whether the RAM is soldered in. As for the CPU, you should always think a little forward when buying.
Your chief concern would be making sure operating temps remain under control. Do so and these should last a fair while.