I have managed at least three teams commercially on four projects in the
last 10 years, and at least two of those projects had over 200K lines of
code. So I guess that would be a yes.

Bug free?

First, the pilot shouldn't be using the handheld in IMC unless...

True. But pilots will do things they shouldn't do, and the equipment
maker gets sued, whether they helped cause the crash or not. This is
expensive even if they win.

Your position appears to be

It's not my position. I am proposing reasons why it isn't done.
Whether is =should= be done is another question, but I can easily see
why they don't do it.

By that logic, we should just stop all technological development,
because God forbid that someone innovates and makes something that is
actually precise, useful, and more advanced than what is already in the
cockpit?

This is the logic behind a lot of aircraft design. I am not a lawyer,
but I vaguely recall a case against (I think) Cessna which came down to
"this design is bad and caused the crash. You knew it was bad because
twenty years later you improved it". I don't know if Cessna won or
lost, but the idea had traction.

In any case, if someone deliberately takes an uncertified instrument and
uses it as a primary instrument in IFR, they are violating the rules and I
guess they are responsible for their own bad behavior.

Well, the pilot does an SPT and kills somebody on the ground, who sues
the pilot, the plane maker, the GPS maker, the airport where the plane
took off from, and the stars in the sky. It comes down to who has more
money from which to collect. If the pilot and his insurance is
significantly less than the GPS maker and his insurance, then any sane
lawyer will go after the GPS maker. The argument that the GPS maker
enticed the pilot to use this device in IMC will likely gain traction
against a judge and/or jury of non-pilots who see many other cases of
enticement for profit.

It =is= the pilot's fault. But the victim is dead and the GPS maker has
more money. I wouldn't blame the GPS maker for being gun-shy about
putting in a feature of less than dubious value in the face of this.

I wish it were different.

Jose
--
The price of freedom is... well... freedom.
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