And now there is more information available about Q: https://qubic.iota.org/

Notice how Qubic will be another protocol built on the Tangle protocol. Exactly like HTTP is build on top of TCP/IP.

You can build protocols on top of Bitcoin too, but when the miners decided to remove the features you were using, and you were fucked. You couldn't continue to use the old standard unless you created something like Bitcoin Cash to get the community of miners you need, but then you lost more than a year and had to invest in programming the reversal of the removed features.

With a real industry standard like the Tangle protocol will become, you will be sure that it will be there in the future too, even if it of course might become obsolete or partly replaced with an even better standard. Like IPv6 works alongside of IPv4, and USB ports that are still backwards compatible with previous slower versions.

The Tangle of the future will be run by totally different software and hardware than today, but if the API becomes an industry standard, you as a developer of things that use the Tangle, do not have to worry about that. If you on the other hand are developing for a platform built on IOTA or EOS that isn't an industry standard, you might have to update your software/hardware when the platform evolves - just like when you have built an application for MacOS or Linux.