This is a growing problem of politics, ideology, public perception.
It doesn’t matter how many people use Snaps. What matters is that Flatpaks exist and provide a good enough alternative for desktop applications, and give you 1 distribution platform with which to reach all of Linux, while Snaps are being marginalized to the point where they may become Ubuntu only.
If you were a developer trying to distribute an app on Linux, would you prefer to reach all users with 1 package, or reach all users with 1 package and then also redundantly reach 40% of users with another package?
Flatpak and Flathub make Snaps redundant, so why should developers use Snaps at all for desktop application distribution? As a developer, wouldn’t you prefer to reach everyone with minimum effort?
When Snaps are being vilified and de-legitimized it doesn’t matter how technically excellent they are. They simply won’t be used and will even be actively blocked, like what the original topic of this conversation is about.
Take nuclear energy for example: new and better and safer reactors have been designed, but they are not used. Instead we keep using old reactors way past their expiration date, like Fukushima. Why? Because nuclear energy has been turned into a boogie man and therefore regulated out of existence.
The same thing is being attempted against Snaps.
If Snaps are illegitimate than all the many interesting and useful things they can do and their technical excellence will be irrelevant. They will simply be shunned by the wider Linux community, and perhaps by over 30% of current Ubuntu users (according to your survey), who, the more you transition to delivering applications as Snaps, the more they will jump ship to another distro.
As far as secondary issues, I do have issues with the documentation. I made a little command-line game called Sparky and wanted to ship it with Gnome Terminal so that I could launch it full screen like a normal game with a .desktop file. I didn’t find any documentation that would help me. I didn’t find any documentation directly addressing what parts are, how to bundle dependencies, or how to add a launcher for my app or the file structure. So I shipped it as something that can be launched only from inside a terminal.
BTW, Sparky is a Snap exclusive. The only other way to get it is to compile it from source.
I don’t think startup times are a real issue. VS Code launches in 3 seconds. Android Studio in maybe around 10 second. Most apps that I’ve tried are around VS Code’s speed or maybe even faster. It’s not snappy, but it’s passable. If nobody pointed it out I wouldn’t have paid any attention.
I don’t think file size is important, because who cares? As long as it’s not huge users probably won’t notice, except for a few zealots of efficiency. What will kill Snap is the issue of legitimacy.