I think you might be overreacting. I felt like you when I heard the news. But then I thought, what the heck, I've got the chance to install W10M on this phone, so why not just do it and see if I like it? So, a couple of days ago, I installed the Windows Insider app, set it to the Release branch, and away it went downloading W10 .107 first. After that installed, it updated all my apps, which took a bit of time, but I made sure the phone was on charge while all this was happening. Then it downloaded .164 and installed that, which was faster. Some more apps updated. About an hour later it was "settled". I restarted, but didn't do any hard resets (I did a soft reset once after it took a bit too long to shut down and seemed to have hung, but it's not done that again).
So, how does it run? As smooth as butter! I really don't know what all the complaints are about. Everything upgraded smoothly, the camera is exactly the same as it was on Lumia camera, though it launches faster, there are actually far fewer "resuming" screens (they were plaguing me under 8.1). The system hasn't rebooted or crashed. It runs cool when in standby (no overheating). It does run a bit warmer than under 8.1 when I'm using an app such as Outlook, but this is no surprise given that the app is so much more sophisticated -- feels very much like Desktop Outlook.
The only downer is battery life when using the phone. It's probably about 70% of what it was, but it's hard to judge because I've been using the phone a lot more than under 8.1 what with trying out Edge, Outlook, the Office apps, etc. I am careful to "properly close" apps if I'm sure I won't need to go back to them in a session.
Try it out, I think you'll be pleasantly surprised. I have been. Unless battery life is a major concern for you (I have the charging shell for my 1020, so I tend to keep it on a charging plate when not using it at the Office and at Home, so battery isn't a big concern for me, and I don't really expect the phone to hold much charge after nearly three years of constant use).
Bottom line is, MS has provided a sophisticated OS for you, and you can have it on your phone if you want it. Try it before you complain so much, and definitely try it before you switch to Android. For me, so far, with no hard resets, W10M is running smoother than WP8.1 on my 1020.
Bugs: I'm not getting active email notifications (banners etc.) from Outlook despite having them turned on. I might need to reinstall it, but the tile shows the new emails, so it's not big deal for now. Cortana is a bit slow to launch, but she hears me fine and location-based reminders are working.
Oh, and if you like it, and MS really doesn't include the 1020 in future upgrades, you can install Redstone with the hack, once you're on W10M. I haven't done that yet, because I don't need it, and I only want stable, release-quality builds.
Is W10M for "the masses" (/sarc) on the Lumia 1020? No, because most people are happy with their phone as long as it works, and they would complain about the reduced battery life in a phone that already had poor battery life on WP8.1, and is probably deteriorating rapidly as it is after 3 years. MS probably made the right decision, but as usual they don't know how to communicate it. They should have said "Hey, Lumia 1020 owners, we've provided you with the option of installing a really good and stable build of W10M for your phones, and if you want to have it, just install the Insider app. However, we've determined that it should be your choice whether or not to install it, because W10M does demand more from your battery, so we're not going to recommend it officially for everyone who is happy with the way their phone runs right now. If you're keen, why not try it out, and if you don't like it, you can always reinstall 8.1 again. If you're happy with how your phone runs now, we'd recommend you stay on 8.1" If they'd put it that way, we probably wouldn't be grumbling so much.