EF Lenses Compared To RF Lenses

[Cantrell]

All,

I have an R10 with RF 100-400mm, RF-s 18-45mm, RF-s 18-150mm, Sigma 50mm ART, Sigma 18-50mm, and a Tamron 150-600mm F5-6.3 Di VC USD G2 lenses. I look at the Canon section of Facebook several times a week. I noticed that individuals are selling and looking to buy EF lenses more frequently than the RF lenses. Why are the EF lenses more popular than the RF lenses? Are the EF lenses better quality or are there just more of them? 

Thanks in advance for your response.

[Cantrell]

March411,

Thank you for the meaning of MILC. 

[Cantrell]

Marc,

Thank you for the additional information.

Reese