If people are willing to pay your prices, they’re not unreasonable.

Some people will only pay bargain basement prices; others will pay top dollar (or £ or EUR) for a high quality product or service.

The only thing you did wrong here is not being transparent with them about your pricing at the outset.

If you are shooting exclusively with RF bodies and you need the weight savings from not carrying EF glass, then by all means sell your EF glass whilst it’s still worth a fair bit (especially the L glass).

If you are shooting a mix of RF and EF bodies (even if you just keep an EF body as a backup in case your RF body dies a sad death on a shoot), then you need to keep at least a couple of EF lenses around to use with it. No point having a backup body with no glass to use on it.

If you have EF lenses for which there isn’t a viable RF replacement (and ‘viable’ might simply mean ‘I can’t afford it yet’), then keep your EF glass and use it with an adapter.

I shoot mostly with an RF body, but I still have my 6D2 and 90D bodies, and I still use them for some scenarios where their attributes are beneficial to me. The APS-C, for example, gives me a useful crop factor for daylight aviation photography (air shows etc.), and I still find I get better results with a true optical viewfinder than an EVF, even as good as they are these days.

Honestly, not really. I photograph air shows, and over a busy weekend I can easily hit around 5k shots. But even with half a dozen shows over the summer months, that’s still ‘only’ 30k actuations. Which means a camera rated for 300k actuations would be expected to last for 10 years.

In reality, it’ll be less of course, because it doesn’t just sit in a cupboard for the other 9 months of the year; I photograph other events too, but those are at most 1k shots per weekend rather than 5k.

Even taking all that into account, the reality is that my oldest camera is a 6D Mk2, released in mid-2017. So it’s at most 6 years old (and more likely about 5, because I’m rarely an early adopter). Both my other 2 DSLRs and mirrorless bodies are considerably newer.

tl;dr - I’m almost certainly going to upgrade/replace the camera due to age and availability of shiny new tech before it hits its shutter count.