Flashable firmware?

Have you ever wondered why more ham manufacturers don't make the firmware flashable like everything else is these days? That way when there is a bug, or a need for a feature they can fix it or add it without having to recall the radio. The ability to update the firmware so bugs that become apparent in use can be fixed.
The ham manufactures tend rush their products to the shelves to beat the completion to the punch. However many times firmware bugs are discovered on the release of radios.

Yeasu and Icom are a good example of this. For example; some of the early release popular FT-8800R mobile radio had an audio problem that cropped up after using it in crossband mode. The work around was to power down the radio after exiting the crossband function. Many people sent their radios back in to have that firmware bug fixed, as do many owners of many other radios.

Two of the new Kenwood's apparently can now be flash upgraded in the field. (Amazing... Finally a ham manufacturer did that!)
http://www.kenwood.com/i/products/info/amateur/software_download.html

Flashable firmware also opens the door to later feature enhancements. For example the FT-8800 also lacks a CW ID for crossband, and something like that could easily be worked into a user downloadable flashable update. Or the new D-Star compatible IC-2820 that has reported audio and callsign display firmware bugs.

So I don't know why any modern design wouldn't use flashable firmware. One would assume the issue is cost. It's a much less expensive to do upgrades when programming faults and misdesigns happen if you ask me.