Renew the lease or retire?

I have a rug cleaning or rug laundry business. In a way, it is like carpet cleaning, but instead of cleaning in the home, we clean in the plant. We can't clean carpets. Our system is based off a 10 hp electric motor for the vacuum and a 3 hp electric water pump. It is not portable. Our blower is different. It sucks about 25-30 percent harder, but can only have about a 50' hose. Carpet cleaning blowers can have 200-250' hoses. They can do about 2000 sf per hour. I can only do 1000 sf per hour.
I have an old 2003, Ford E-150 van. It isn't going to last much longer.
From 2005-2017, my weekly sales were $1,200 to $2,500. Last year they ranged from $800-1,500. I don't know why. They were worse this year. Have broken $1,000 only once. Have not broken $500 per week in sales the last 7 weeks. I cut my helpers hours and they quit. I have a small warehouse space, 1,400 sf and the annual rent is $7.50 per sf. The landlord knows I'm slow. He has lost half his tenants the past year. He offered to drop it to $7.25 if I sign a 2 year lease.
I have no idea while I'm in freefall. I'm 55. I've been in this business 38 years. I opened my own place in the fall of 2004. We're servicing the outer and middle suburbs of NYC NJ and Westchester/Hudson Valley. We used to go over to Stamford, CT for a few years, but stopped that last year.
Should I just give up? I have no clue why this happened.

Added (1). We used to do $300-500 a week wholesale for dry cleaners. We haven't done $500 all this year for dry cleaners.

Why do you need the warehouse? I knew a guy in the business 20+ years ago and he did not have a warehouse.
Are you bidding for work?

I have a friend that doesn't was rugs, but he does wash those entry mats. Business is booming! He does $2,000 a week in the summer and $4,000 a week in the winter with rentals. Big companies like Cintas or Unifirst grab 90 percent of the work. But if you are a single unit mom and pop place, with 3 mats, they are too expensive.
Diversify?