The more of this kind of small vehicle traffic we get the better supported it is. Safer traffic patterns, dedicated lanes, repair stores and vendors, etc.
I think you're also seeing some political organizing to that front, too. Cambridge MA has a biking advocacy group putting pressure on government to put in more biking infrastructure.
Big car might have a stranglehold on big government but people paying attention to small local elections can make a big difference
Constituency building is absolutely crucial to all of this and often underlooked. It's a virtuous cycle. If you build useful and good infrastructure, people will use it, and the more people who use it the more people who will vote for it and demand it. It's a big part of how car-centric urban design grew so fast and became so sticky in North America, and that same constituency-building is the best way to take streets back for people.
Seeing people on bikes makes people think about biking. Even without the bike paths, being out and about your city on a bike is doing your part to build just a little more constituency for it. On top of it being good for your wallet, the climate, and likely your health.
Now if only I could get the average local bike shop worker to stop being such a colossal gatekeeping prick about ebikes...
Yeah, Cambridge, MA has done a lot. The last job I had there was on a newly renovated building and per city regs it had to have a full bike room and showers. I thought it was oversized but obviously welcome, but by summer it was over-full. Though the space could be much better used.
That summer at one intersection I was stuck in congestion - bike congestion. There were 30 commuters ahead of me at the light on the way home - a light that 6 or 7 cars got through per cycle.
It's far from perfect, but just cross the river to Boston and it's a different world, even though Boston has probably improved more than most US cities too.
That said, the North end has a wonderful separated bike lane.
Well there I part ways with a lot of local pro-cycling opinion. Separated lanes are only superior under tightly controlled design, and most around here are far from that and give an entirely false sense of security. They're often hidden behind parked cars and every intersection is highly stressful minefield of interactions with drivers completely unaware of your presence. That Commercial St path in the North end is not separated at all from pedestrians and is (belligerently) considered by most joggers to be a their path, and pedestrians don't think of looking before lurching into it unpredictably. Even the stretches where the pedestrian area is 15-20ft wide, the majority of joggers use the bike path, and where it's crossed by side streets and parking entrances, cars will just blow through your path.
The Seaport Blvd "separated lane" is f'ing lethal. The Somerville Beacon St lane made things significantly worse IMO. I commuted that regularly before when there was just a big wide lane rideable without any drama or difficulty. After the new lane I only rode it 30 or so times and with the near misses I experienced or witnessed mean I avoid that route eastbound if at all possible. Now it's a hidden lane behind parked cars where motor traffic often doesn't notice cyclists and blows right across your path.
Separated lanes are the ideal when they're done right, following best practices, e.g. from the Dutch, which means not on roads with many crossing intersections, and at intersections the lane needs to be carefully managed with a significant period pulled out clearly beside the motor traffic lane before the crossing.
After a dooring 18 years ago I've been very careful passing parked cars in general, but a false sense of security in a segregated lane, and a brief failure to recognize the danger, means I was doored again 3 months ago, from the left. Frankly it just confirmed what I've been feeling over the last few years about unsophisticated "separated lanes good" attitudes. A lane painted alongside traffic is often not inferior in reality, in my experience, even if (and sometimes because) it doesn't make people feel so secure.
Keep in mind, there's a lot more that goes into the wildly superior Dutch infrastructure than just which streets get bike lanes along them. Roads are also fundamentally deferential to pedestrian and bike traffic there. As in, crossings are elevated above the road, which has a surprisingly effective impact on the culture and behaviors around modes.
The other issue with bike infrastructure in MA is also the reason we see pockets of it done so well-- cities here have way more power than in other states. It's a lot easier to get this stuff implemented here with purely local efforts than, say, in WI or wherever. We also just straight up generally love biking here. It's still totally baffling to me how that fucking gremlin thought he could run for mayor of Somerville on an explicitly antibiking platform. I also wish we could get our shit together in Medford on this, but my city is so god damned broke, I don't think we could afford the paint for slapping down lines.