The infamous Todd Howard from Bethesda has gone on record with GameSpot to state that he regrets not having a free beta for Fallout 76 before launch, so the idea could have been communicated better to fans.
While there was a beta for those who pre-ordered, this did little to quell the concerns of the detractors, who naturally would not have done so. Although free keys that were given to friends did address this to some degree, Todd felt like the message of what the game was about could have been better communicated with an open free beta;
My main regret is not doing a beta that a lot of people could play, if we had made it free for every Fallout 4 player and run a 24/7 beta, for a longer period of time, that would have let us see, OK, what are we really dealing with here?
Todd also expresses his thoughts about how the beta was handled in terms of time limiting. The beta was very much limited to certain time scales, to basically test server loading, and as such didn't give much insight into the longer term implications of a 24/7 game, such as the various item glitches and other issues.
The betas we did were concentrated because we were worried about peak concurrencies, so we got those issues solved, but didn't get a good look at, how does the game really behave at scale 24/7. So that, you know... learned that lesson the hard way, but wish we had done that.
So, these are perhaps two things that Bethesda will learn from going forward. One other big complaint about the game, the lack of NPCs, is also set to be addressed in a future update to the game. Stay tuned for more as we learn it.