There’s a distinction to be made here between CPU and GPU performance. Apple Silicon is fine on the former, less so on the latter (by desktop standards). In terms of GPU, no particular ‘beefing up’ is required, just specify any half-decent option at the Mac Pro checkout. The prices are high; it’s ultimately up to the customer to decide if macOS is worth the difference vs a PC.
The want very powerful machines, rather than ‘upgraded’ per se. GPUs are a fast-moving category, however, so it’s likely such users will want to upgrade them during the life of the machine.
Which ‘pro software’ are you referring to? Most will run fine on a MacBook Pro. The class of applications that need powerful GPUs is smaller, but a Mac wouldn’t be the ideal pick for 3D animation, (non-iOS) games development, Virtual Production or Machine Learning. Generally because Mac Pros don’t support Nvidia GPUs, offer poor value for money in those roles, and / or the software runs better under Windows or Linux.
Also, define ‘many people’. Apple’s long-term ambivalence towards the Mac Pro suggests the number doesn’t meet their desired economies of scale. Pricing it high to compensate will have shrunk the machine’s user base even further. Unfortunately, Apple had already tried reducing their costs (with the 6,1 and iMac Pro), and that didn’t work out - the resulting products just weren’t what (enough) pro customers wanted to buy.
For a whole bunch of reasons, Apple’s sweet spot for the Mac platform seems to be laptops, and desktops that essentially use laptop hardware.
