No, I'd say that is a false assumption. When so many people bought F4, they only had Fallout 1-3 and NV on their minds, not what this creation is. Now that F4 is out, all future purchases will be with F4 in mind, and there are actually a ton of people who feel the same way as I do, as the ratings this game has got show.
Good business practice is not pissing off your customer base, even a segment of it, and continually deliver what they want. I suspect they could not meet their goals, so pushed what they had forward, using modders as a fallback excuse for every last bug and problem this game has in plenitude. Am I going to make assumptions about this crew a second time? No way, you can only fool me once before you loose your reputation. Those of us who do not bend over for Bethesda and make lots of excuses for their errors will probably do the same.
The gaming community needs to hold gaming companies like Bethesda and others accountable for their actions. If Apple released the iPhone and it had a ton a problems, they will get eviscerated for it. Not so gaming companies, because a lot of you people out there keep worshiping them rather than holding their feet to the fire for bad decisions.
Fallout 4 has a lot of good, but a lot of really bad decision making as well. My guess is the true programmers at Bethesda stayed true to the spirit of Fallout but some schmuck executive demanded the 'streamlining' of the Fallout premise in some short sighted console worshiping or smartphone app enthusiast prerogative.