I work in IT for my day job, so I am very familiar with what happened with AR15.com and what they did to address it short-term.
Can it happen here? Short answer: Yep. While I can institute a static IP with my hosting provider (which is not a big cloud provider; ie - not AWS, Azure, Google, etc - and no, not GoDaddy either), there is a cost to it. And doing that would simply allow you to go to an IP address in lieu of the domain name. DNS is essentially just a service on the internet that translates the web sites we visit from IP addresses that look like 68.105.28.11 into something we can easily remember for convenience. GoDaddy essentially deliberately prevented AR15.com's DNS from working during the outage. If you knew AR15.com's IP address (actually, they have 3 front ends that are load-balanced due to the traffic the site gets), you could still get to it.
ar15.com. 5 IN A 3.20.37.167
ar15.com. 5 IN A 3.139.193.203
ar15.com. 5 IN A 3.138.255.236
While I'd love to be able to build AZS in a resilient and redundant fashion with full DR (Disaster Recovery) and a quick RTO, this site is run entirely at my own expense with the help of a few generous patrons who throw a few dollars to help each month. This site generates no profit, so anything I do is at my own expense. To that end, I do take twice-daily backups which are stored at the hosting provider (for quick restores) and off-site for security. However, the site doesn't have a DR environment or a cold/off-site copy ready to spin up - to have that would more than double operational costs and complexity.
When I first built AZS (the old one, a LONG time ago), I actually built it on my own system at home and hosted it through my home router. That was when most ISP's didn't restrict or prevent their customers from running a web site from home and DSL was synchronous, meaning that I had just as much upload as I did download. Today, most ISP's heavily restrict upload bandwidth to prevent hosting web sites.
The internet today is heavily distributed and it would be very difficult for Big Tech to bring down access to all sites like AR15.com, AZS, etc. Could it be done; yes - but it would either need to be vastly coordinated at a level like nothing before we've ever seen, or it would be done in waves with the big stuff first, and then gradually move on to the rest.
Given the influence that the players have (Google, Twiter, Facebook, Apple, Microsoft, Amazon, politicians in power), it would not be too much of a stretch to have them exert influence to hardware vendors (Cisco, HP, Dell, etc) and major internet backbones/routes (Verizon, TimeWarner, etc) to not sell or support environments that host undesirable content, or to de-prioritize, blacklist or block entirely, certain web sites or worse, entire ISP's who allow routing or traffic to those undesirable web sites.
It's scary to think about and it is certainly not something that could be done in a day or a week, but it's certainly more plausible than I would have ever thought if you'd asked me 3 months ago. I know that doesn't quell any fears, but I also know that if all that were to happen, you'd have a lot of rogue sites that would pop-up and it'd be like playing whack-a-mole for them to try to stop it all.
Be prudent. Unfortunately, in the world of today, it's pretty much impossible to be involved economically or have a job and not use some aspect of the Big Tech companies I mentioned earlier, but it's also worth having a backup plan, just in case.
Make sure you have a free Protonmail account.
Consider downloading Tor while you still can (https://www.torproject.org/).
Consider changing from Google to DuckDuckGo for web searches...
We're in a whole new world and the next couple years are going to be very interesting to say the least.
