I've been slowly working for years on letting clover take over my lawn. I have amazing flows of white flowers in the spring, with the red clover now starting to come in as well. I mow it once the flowers pop up to force the growth back down into the root systems, and I've converted more than half of my 5 acres into clover at this point. It also is speeding up, and will probably be fully clover within a year or two.
My point being - your UX doesn't ask what people's goals are. Not everyone wants a "perfect lawn". Even people who do want grass may have different priorities for their grass - low maintenance vs. low water usage vs. really green, etc.
If you want your product to be different than what the lawn care guys will say, then you need to actually let people do different things in the app. Or, if you are dead set on making this into lead gen for lawn care guys, well... I personally find that somewhat disheartening, but clearly I'm not your audience.
The real proposition here is diagnosing the specific problem and offering specific fixes for said problem. I think the platform provides a good opportunity to present alternatives to the user other than "just fix the problem" and says "have you thought about this instead?" But since the primary user is trying to fix the issue, I don't want to necessarily try to force alternatives my audience isn't looking for. That being said, one option would be to give an option in filling out the form to ask what their goals are, such as "I just want to fix the problem" or "I'm open to exploring new ideas for my lawn."
It's not "just" for lead gen. I'm actually trying to help people and solve a problem. I want the tool itself to be free. It monetizes by means other than making it a paid tool.