So it's modular. This is normally considered a good thing. It means you don't have to pay for features you don't need.
The ISA is open so there's no greedy corporation trying to upsell you. I mean there's an implementation and die area cost for each extension but it's not being set at an artificial level by a monopolist.
There's a good chance you're actually paying more for the features you don't need. Preparing an EUV mask set costs something like 30 million dollars (that figure may be out of date, i.e. it could be more now). So instead of a single mask set with everything on the device, whether you need it or not, you're paying $30 million for each special-snowflake variant. This is why vendors do a one-size-fits-all version of many of their products and then disable the extra functionality for the cheaper market segments, because it's much, much cheaper than making separate reduced-functionality devices.
It's a good thing in many cases but not if you're going to be running applications distributed as binaries. Maybe if we go the Gentoo route of everybody always recompiling everything for their own system?
But that means a port of Linux can’t be to RISC-V, it has to be to a specific implementation of RISC-V, or if sufficient (which seems still debatable) to a specific common RISC-V profile.