BSI sensors don't require new litho machines. On-chip ADC doesn't require new litho machines. I even doubt the rumored 60-80 MPix sensor doesn't even require new litho machines as it is the same density as their current APS-C sensors.Because part of making your own chips is owning and operating your own Fabs.They already do it, not for their DSLRs but Powershots, the G7XIII and G5XII use presumably Sony RX100M4 sensors which are not the newest.Nikon is using Sony's sensors. So could Canon, if they wanted to. That includes both options: 1) Design the sensor themselves, but subcontract Sony to fab it, or 2) Buy one of the sensors Sony already sells to whomever wants them.
The problem is that Canon wants to manufacture their own sensors. Here are the reasons:
It is their good right, but why not a new design ? Even, as I said before, the R and RP use older design sensors. What some say in this topic, these cameras are not cutting edge technology.
I am a Canon user since 1986 when I bought the T90 which was more cutting edge for that era than the R(P) now. Much easier user interface with a wheel (which many cameras have now) and no clunky mode dial on top (still present on modern cameras in 2020).
I still have the 6D (first edition), considered an upgrade to the R(P), but for me it is, despite better AF and tilt screen, not innovative enough.
Canon should upgrade the R(P) with an EOS R Mk2 within two years with a real innovative sensor and more builtin computational photography and regular firmware updates.
Otherwise Sony will blow it away with the A7S4, a cheaper cousin of the A7R4 probably released soon.
And you can't produce new sensors that have BSI or stacked memory without upgrading the fab first.
Those 2 things (and others as well) are not just a "design". They require new updated equipment to manufacture.
Plus it actually gets worse. Goto the link that I posted about Canon's lithography equipment. If Canon has to use their own fab equipment in their own fab, then in some cases they have to upgrade that equipment first.... then the fab facility they use to make their own chips .... then their sensors ... and finally the cameras that use them.
THAT is the reason it takes so long.
Where Sony sells chips to everyone else, they get to stay ahead of the curve.
The good thing about this rumored high-MP canon EOS-R is that they cannot re-use the 5Ds sensor as that doesn't have DPAF. So they have to design something new. Hopefully it's something really new, and not just an upscaled APS-C sensor from their 80D.