The entire question really is nonsensical.
Base your purchase on your requirements & your budget now this moment in time.
Intel if you're primarily gaming , running a 144htz screen & want max performance on AAA titles & are pairing it with a high end gpu from the gtx 1070ti upwards.
Thats a big budget though there & a long term investment imo.
That said with the brute power the 8700k has it will still be a viable chip 5 or 6 years from now imo.
That comes at a cost though as I said , you can buy a ryzen 1600 & a decent b350 board together for way way less than a 8700k on its own & you also need a $100 cooler in there with the intel too if you want to push max performance from it.
Below 100htz the ryzen will do just as good a job for the next 2-3 years anyway & at that kind of cost difference you could include a full platform replacement when you want to change for the same budget in total.
Peripherals ?? Pci-express ,sata, m2, ddr4 ??
The standards now will remain a constant for a long long time to come , carrying other components over into future platforms shouldnt be any issue