I'll be as fair as possible here.
You posted a zip demographic tool.
You posted numbers for yourself.
The numbers are from a zip code other than your own, numbers that are substantially higher than your zip code.
Who is pretending?
Lowell has improved dramatically over the last 20 years and does have some quite affluent sections now. Then again, it always did have some money areas, because of those mills. For the 50 or more before that it was one of the very worst areas of MA with the some of the highest crime rates and poverty rates in the state. That doesn't make it anything like Chelmsford yet. You do live in a nice section... of Lowell.
Lowell's heyday was 100 or more years ago when those textile mills were making money, right? I'm talking about the textile mills that over the last 30 or so years Lowell has tried very very hard to turn into museums, historical sites, tourist attractions. It hasn't worked all that well. There is a reason for that. If you are interested in why the residents of Eastern MA still view Lowell the way they do, do some research through unofficial sources on who worked in those mills, what the conditions were, and where all the profits went. After you do that you'll understand why Lowell has the legacy it has in this state. You'll also understand why the tourism industry there wouldn't take off... no one wants to remember those places.