You need leverage.

The objection "you might not be around in awhile" is semi-valid but not a deal-killer. Something else was missed.

"So are you saying you would NEVER, under any circumstances, work with a company less than a year old?"

I'd go back to prospects who have turned you down and ask for open, honest feedback. Tell them it doesn't matter now, since they said no anyway, meaning it's not going to hurt your ego and you really want to know the real reason.

In future presentations, don't bring up the age of your firm.

Have a proven industry spokesperson endorse you.

Develop a ton of content that shows you are in the field, are known by other people in it, and are at the forefront of whatever it is you do.

And make sure your SaaS really does solve a HUGE problem for your market.

Why does your marketplace--not YOU--say they need it?

Remember that your customers survived to this point without it. Why should they change? There are many other sales process factors that we cannot see from the outside here.