I will note that you listed out all of the RVA23 instruction extensions, not all of the blessed RISC-V instruction set extensions. Here's the list of every ratified RISC-V instruction set extension, to get parity with the list you gave for the other ISAs:

M, A, F, D, Q, C, B, H, Zicsr, Zifencei, Zicntr, Zihpm, Zihintpause, Zihintntl, Zicbom, Zicbop, Zicboz, Zicond, Zicfilp, Zicfiss, Zimop, Zca, Zcb, Zcd, Zce, Zcf, Zcmp, Zcmt, Zcmop, Zclsd, Zilsd, Zmmul, Zfh, Zfhmin, Zfa, Zfbfmin, Zfinx, Zdinx, Zhinx, Zhinxmin, Zaamo, Zalrsc, Zawrs, Zacas, Zabha, Zalasr, Zba, Zbb, Zbc, Zbs, Ztso, Zbkb, Zbkc, Zbkx, Zknd, Zkne, Zknh, Zksed, Zksh, Zkn, Zks, Zkt, Zk, Zkr, Zve32x, Zve32f, Zve64x, Zve64f, Zve64d, Zve, Zvl32b, Zvl64b, Zvl128b, Zvl256b, Zvl512b, Zvl1024b, Zvl, Zv, Zvfh, Zvfhmin, Zvfbfmin, Zvfbfwma, Zvbb, Zvbc, Zvkb, Zvkg, Zvkn, Zvknc, Zvkned, Zvkng, Zvknha, Zvknhb, Zvks, Zvksc, Zvksed, Zvksg, Zvksh, Zvkt, Sm1p11, Sm1p12, Sm1p13, Smaia, Smepmp, Smstateen, Smcdeleg, Smcsrind, Smcntrpmf, Smrnmi, Smdbltrp, Smmpm, Smnpm, Smctr, Ss1p11, Ss1p12, Ss1p13, Ssaia, Ssccfg, Sscsrind, Sscofpmf, Sstc, Ssqosid, Ssdbltrp, Ssnpm, Sspm, Ssctr, Supm, Sv32, Sv39, Sv48, Sv57, Svinval, Svnapot, Svpbmt, Svadu, Svvptc, Svrsw60t59b, Sdext, Sdtrig

That doesn't look very short to me.

These are grouped into profiles, like "Skylake" or "Cortex-M33" or "Neoverse-N1." The main issue for RISC-V isn't the number of instruction set extensions, it's the number of profiles. RVA23 is one single blessed profile, but many chips will add a few more instructions or include fewer than RVA23 based on age of the chip.