If only they reproduced the sound more accurately! Convenience is one thing, sonic accuracy is yet another!
I prefer convenience too... but I won't elevate them to being the equal of the originals!
The Tyros4's organs are very well done. A friend has a Hammond XK3c, and I can play a note on my T4 and the same note on the XK and they are pretty much identical for all settings. That's close enough for my needs.
Electric pianos, including a great Wurly, are excellent, plus I have all the other sounds not on B-3 or Rhodes, plus a whole brace of effects and layering possibilities. And we haven't even touched on programmable auto-accompaniment, sequencing and audio recording.
For the tiny gain of accuracy in some instances, it's just not worth the hassle of the average musician lugging around and maintaining old gear with all it's disadvantages.
Comparing those old instruments to a new keyboard is like comparing an old Cadillac Sedan to a new one...they are both great cars...just from different eras and for different users.
But, I could still carry my Tyros4 in either Cadillac...not so a Hammond B-3.
Thankfully the days of hauling that old gear and having to have a van to move it are way behind us.
I don't miss those days one bit.
Ian