The mac mini is essentially 1700 days old since they downgraded the processors.
I only have macs because I build apps on them. I buy used and as inexpensively as possible. Using an old i5 for development currently.
I wanted to be an Apple fanboy, but having to rebuy critical software for even point releases because of stability killed that off for me long ago.
Best Apple I've ever owned (beyond my //e) was the Dual Processor Quicksilver. Case opened on the side, you had many upgrade options and it even looked nice (irrelevant to me but I'm sure that matters to some).
ARM will simply be the new PPC. You think things like supporting external graphics cards (yay they just got limited AMD support) and having high end rigs isn't what people want, especially in the gaming community?
Apple will not suffer in 2020 from having lower performance than intel. It wont matter. Form factor, screen quality, memory speed, memory size, touch pad, battery life etc will matter so much more.
Multi threading is also so much more common on pro app which require performance. They can just match intel by using more cores. ARM is way cheaper than intel so I don't see how they can lose this game. PPC was an entirely different world.