That is a fair argument and the points you made can't be dismissed. But a lot of other big clubs from the late 80s had an even bigger fall from grace in that period. Leeds for example won the league in 91/92 and then saw a massive decline not too long after. Sheffield Wednesday have spent the majority of their time outside of the top league. Nottingham forest were a big club too and saw themselves until recently outside of the top flight.
Yeah it's desperately disappointing that we didn't capitalise on the premier league when It was formed like the likes of Arsenal, Liverpool, Manchester Utd did. But we weren't the only ones. As advised many others struggled. I just don't think it's as straight forward as just blaming Bill for everything when in some ways it could be said that he saved us when other teams like Leeds, forest and wednesday fell into the abyss for so long.
Maybe the investment never was there, and when it did arrive with Moshiri the rules had changed stopping us from being able to do what Chelsea or City did.