Ok, so I think there are two distinct questions. First, is the B1G a good lacrosse league? Second, how long will it take to catch up to the ACC.
The answer to the first is yes. Maryland and Hopkins lend some credibility to the league but tOSU, PSU and Rutgers have performed pretty well over since the founding of the league. I looked up the historical results and in '17-'18, Maryland, Hopkins, tOSU and PSU made the tournament. Rutgers hasn't made the tournament since the league has been founded but has been on the bubble a few years (and should probably have been in at least 1 year). We have a pretty solid league. As for Michigan...oh boy. They certainly have the money and ability to invest in everything but they have A LOT of work to do. In 3 years they are 1-14 in conference play.
Go here for B1G lax stats. All time standings are at the bottom of page 252 and NCAA Lax tournament appearances are at the top of page 270 (I wish I was more computer literate so I could integrate these to the post.)
So the second question, when will the B1G catch the ACC? This is a much more difficult question to answer. My answer is probably 10 years minimum with the potential for never. The ACC schools just have to much of a head start. They have the history. While they aren't currently in the same financial realm as the B1G, they have money and the desire to invest. The B1G has the money (currently) but not the history. In my mind, history is more important although money is still a big factor.
Now comes the "fun" part. What is going to happen with Hopkins. Short answer is I have no idea and I haven't heard anything. Believe me, I've been keeping an eye/ear out for scraps of info. My thought is that Hopkins is very likely talking to the ACC. They previously were not interested in partial memberships but now...? I'm not saying they are leaving but I'd be shocked if conversations were not happening. I think the B1G NEEDS to be discussing the possibility of them leaving and what actions should be taken. Who does the B1G call up? I think the B1G schools that might be most likely/able to regain the crucial 6th member are schools in the east. MSU could restart their program. Maybe Indiana. Northwestern would be a good place to look since they have an existing women's program. Obvious issues would be money and title IX. There is the potential for looking at someone out west. A REALLY dark horse could be if UConn starts a program. They have a ton of financial issues but they are in a talent rich area and I'd expect that if they start a program, it'd be pretty darn good in a short amount of time.