I disagree. Computers don't get slower, but the WWW becomes heavier and heavier, and for many old computers it's become too painful to browse. Even a simple HTML5 game doesn't run smoothly on my X220.

And as for Intel ME: it isn't that hard to neutralize it, I did it on my own computer recently. Even if you apply that on a newer computer where not all the code is deleted, you can be pretty sure it doesn't spy on you. After neutralization, Intel ME only runs during the startup process, and even then it doesn't have a TCP/IP stack.

Newer chips are faster and more efficient, so you get value for your money. If you don't do any intensive stuff, then weaker hardware will suffice. It's not like all new computers are crazy expensive.

Regarding breakability / hardware being hard to replace: that seems to only apply to laptops (unless something changed in desktop computers that I'm not aware of in the last 5 years). His advice does have more relevance in that area, also because older laptops have better keyboards. But the choice is limited. X220 is a go-to option, but again, it might not be capable of everything you want to do with it. Intel HD 3000 is a limitation. And the batteries of older laptops have degraded, so you have to get a 9-cell battery and carry more weight for less battery life.