I don’t know why people get so hung up on the Pro label. Whether Mac, MacBook, iMac or iPad, it simply means higher specs/performance (which naturally is more expensive).
Plenty of pros use the regular MacBook, iMac and iPad models; similarly many home/consumer customers also buy iPad Pro and MacBook Pro, though relatively few buy Mac Pro or iMac Pro for obvious reasons.
I think it is because the definition of 'pro' at Apple has seemingly changed and your response points that out.
Pro, in terms of tools and gear, used to apply to the product being of higher quality, durability, capability, etc. It was a quality of the object, not a marketing term.
As you point out, a
professional lawyer could use a Chromebook, and in that sense of use, it is a pro product if it were aimed more at that
professional market.
When it comes more recent Apple equipment, it is kind of a mixed bag. Certainly the Mac Pro (cylinder) and iMac Pro are more in the category of substantially different hardware dedicated to professional uses. The previous Mac Pro (cheese grater) was especially like this.
While Apple's laptops have always been a bit non-pro in certain ways (like not being able to push them with heavy jobs w/o damaging them), they were more suited to professional use and environments. Maybe that is just a liability of laptops, though one could imagine a pro laptop (in the sense I'm using the term) could be made.... with tradeoffs Apple (and maybe even the majority of professional users) wouldn't buy.
Certainly, most of the pro models have more performance or some higher capacities. What has been missing, is more the durability and flexibility to cover a broad range of pro use. For example, dramatically limiting the ports on the pro laptop creates more difficult situations for professionals who regularly use the ports. Yet, maybe a lot of people who do development work on coffee shop tables love that aspect if they gain some extra portability.
Basically, the two have become more similar in inconsistent ways. Pro has come to mean a bit fancier model aimed at people who will spend more money to up-purchase a bit higher end model. It doesn't mean that if you buy the pro model, you can safely use it to do higher end work, nor might it have the capabilities it would have had a product generation or two back.
Note: this has happened in other industries as well... sometimes where the 'pro' model isn't much better at all, just fancier packaging or labeling.