Im not worried personally,
window cleaning has changed since I started 29 years ago. back then it was the norm for customers to be every 4 weeks.
the majority of my 4 weekly, have been with me for 10/ 15 /20 plus years.
when I build on my customer base these days from flyers / website/ walk ups..... I recommend every 8 or 12 weeks, but charge more...it just makes sense to get as much as you can each clean.
and the customer seems happier with these intervals, as its still cheaper than 4 weekly for them.
for a start up, it just takes too long in most cases to build an 8 or 12 weekly round.
A lot of start ups need the work rapidly, and may not understand the importance of that first clean charge. IMO a first clean charge is a must.
I often see a new cleaner cleaning a customer I have binned for being messers, skippers or bad payers, and I feel sorry for them.
but good luck to those new start ups. some will do well, but most will struggle, when they realise its harder than they thought