Excellent questions! It isn't a measurement issue because we've actually measured the uncertainty. The uncertainty principle can be expressed as a mathematical equation, which you can then go onto use to derive all the rest of quantum. We've used those to create and understand new technologies, like the electron tunneling microscope. Electron tunneling is also the underlying phenomenon behind chemical bonding.

As far as why it's impossible to know the exact position and speed of an object, the answer isn't very satisfying -- it's just how the universe works. Learning quantum at first requires a suspension of disbelief to some extent, and it's not one you need to do on faith. If you look up the double slit experiment, it's a rather simple setup which demonstrates wave-particle duality, and how observing a wavefunction collapses it. It shows us that uncertainty and quantum fuckery is part of the natural world.

One immediate follow-up question is why we can know the exact position and speed of objects in our everyday lives, which again, is a very good question. The uncertainty principle technically states that we can't know the exact position and momentum of objects. If we let dX represent uncertainty in position, dP uncertainty in momentum, and dV uncertainty in velocity:

dX * dP = constant

Momentum is just mass times velocity, so:

dX * m * dV = constant

dX * dV = constant/m

This tells us that the product of uncertainty is going to be inversely proportional to the mass of an object. So the bigger something is, the less uncertainty there is about its position and velocity. When something gets really small, say atomic and subatomic sizes, the uncertainty gets very large.

Sorry if this is way more detail than you wanted. I took a few classes in college that touched on quantum, and Physical Chemistry was pretty much all just quantum. I had an excellent professor for it that showed us how you could derive all of it from the uncertainty principle.

It's because the concept of a particle having definite properties like position and momentum doesn't hold in the quantum world. Until a measurement is made, the particle is in a superposition of all possible states but with different probabilities, these are described by its wavefunction, which encodes what the various particle variables (position, spin, momentum, etc.) could be.

So, it's not a measurement issue that introduces the uncertainty; it's already there as a fundamental property of the particle's quantum state.

Measurements merely "choose" one of the many possible outcomes, collapsing the wavefunction and in turn making exact measurement of other complementary properties impossible (because the mere act of measuring one variable causes the system to transition into a new state with its own set of probabilities and uncertainties for all variables)

And because these are inherent limitations dictated by quantum mechanics and the uncertainty principle, even if we could know the current state of every particle in the universe, we still couldn't accurately predict the future because of that fundamental uncertainty.