Focusing just on laptops would avoid the expenses and complication of a fairly niche line of computers.
Are more Studios sold than Macbook Pro?
If people need more, Apple could offer cloud computing access at a monthly or yearly subscription cost or a "power by the hour" arrangement.
There's a category that Apple has been serving since the 1980s, the creative professionals. A desktop is a requirement here. Studios, production houses (think film production, motion design, graphic design, music production [Hans Zimmer, music producers],) etc all will need desktops so the Mac Studio fits in here, not the Mac mini (which is constrained with thermal limitations and tops out with RAM/GPU and M Pro chip)...The Mac Pro most likely wasn't selling well, and after the Trash Can and delay for 6 years a lot of people moved either to PC (3d professionals) or iMacs or held off and got the 2019 Mac Pro and now the Mac Studio. It was most likely 1% of their total sales and weaned off after the M2 Ultra update. It was a slow death (intentional on their part or not).
MacBook Pro's are definitely sold more than the Studios, but that's not the point. This category, Apple will not get rid of—ever. It's their foundation, not bread and butter. Apple sells products and an ecosystem, so if you are getting a Mac Studio you most likely also have a MBP, iPhone, iPad, Watch, or whatever and their services. That's what they want.
Cloud computing is not feasible for what I'm talking about.
I did some research lately and since the M5 Max is already out, it seems that the M5 Ultra on the Mac Studio is going to be a huge leap (30%+ in CPU + GPU) from the M3 Ultra in many scenarios and the maxed out M5 Ultra GPU will compete with the RTX5080 Laptop version for sure (not the 5080/5090 Desktop)...maybe M7 Ultra (in 2028) will do that with new thermals/redesign, but that's a lot of horsepower in such a tiny package. It's still an incredible leap.
MacBook Pro's are not good desktop replacements although I've worked in some places lately which just give you a MacBook Pro and then we dock it to a screen, that gap has narrowed, but it's still not covering the category I'm describing above.
The Mac Studio also covers a new sub-category of users: AI/LLM coders and what not, but that also fits into the "creative professional" category. They have no competition in this area at all, unless you're talking about super computers.