I think there is money to be made on both sides of the coin. On one hand, break-fix.. on the other hand you have managed services and continuing services.
I believe a lot of folks here have a specialty in one, and prefer that, and advertise for that and it's skewing everyone's perspective. If one goes on Google looking for screen repairs.. it doesn't give priority or even first page to a managed shop.. a perspective filter.
So for a continuing services provider, break-fix looks like a dead industry, they don't really know about hardware or electronics at it's basic level, it isn't their game, etc.
For break-fix folks, continuing services and management isn't their game, don't see the value as a small shop, etc. insert reason here.
There is money to be made in both sides. I do (until corona) a ton of break-fix work and make a good living at it. I also do managed services and make a good living at that. Both combine to make a 'sustainable' business.
I think the biggest thing is, don't focus on being a "Break-fix shop" or a "Managed services shop". Pending your abilities, time, efficiency and spending cash/frugality?... some of the decisions will be made for you, regardless of your plans. Be a full-circle shop and simply offer what clients in your area are asking for. Yes, technology is changing. Yes, we will have to move forward with it, not against.
All that being said.. I charge $150-$600 for laptop screens depending on model... my average take is 60-80% when counting parts cost.. that's not bad for 10-30 minutes of my time. I do hundreds of screen repairs per year. I do hundreds of motherboards, hundreds of hard drives, etc.
I have been doing business managed services for the last 5-6 years and it also provided great benefits as far as income, but also for getting my name out there. Manage a Church... do a good job and the whole congregation wants their personal computers fixed, antivirus, etc...
So a "Managed job" and a "Break-fix job" really do work hand-in-hand at some level.
Your first 3-5 years will be the worst, toughest years. I literally dumped money into advertising on Google for the first year or so, at least it felt like it.. But, that got my page listed at a primo spot, the good reviews rolled in and now my listing is natural... I don't pay Google anymore.
I say go for it, just don't limit yourself to thinking you can only do one kind of task. Stay vigilant and if your area/customer base/other local problem doesn't support you.. change or quit.. don't keep going on a failing path. When you know to look, it's easier to see.