This is the problem with small cities' public transit systems. Temporal flexibility is limited compared to driving one's self to work. Need to stay late? You'll be staying all night, or your spouse must come pick you up.
Other issues (observed as a lifelong Clevelander):
1. The elapsed time savings of using public transit is often quite negative (compared to a city like NYC where it probably is often more time-efficient to take the train).
2. Parking costs are relatively low, so there's no tax on bringing your car with you to work. And, you almost never pay for parking at home.
3. You can't live easily without a car, so the potential savings of public transit is reduced to less usage of your current vehicle. You still have to own one, pay for insurance, etc.
4. Density is so low that your first/last mile issues may literally be that far.
All of this creates a death spiral for these public transit systems: Ridership is low, so vehicle frequency is low. This creates higher costs of public transit for people who have more money than time (how much could you have earned while waiting for the bus?), so these systems end-up serving only those with more time than money. This creates a stigma around using public transit which further reduces ridership. Add in white flight and the fear that extending public transit to the "nice areas" will allow "those people" to invade, and it's hard to imagine how public transit could ever work.
The RTA is very good for getting downtown or to University Circle (and possible Ohio City). Unfortunately the jobs have all moved to around 271/480. I did the 48->7 reverse commuting from Shaker Sq. to Highland Heights when my car was in the shop last year. Let me tell you, that sucked. Nearly an hour and half vs. 30 min driving. And there's only 1 bus the entire day that took the special route I needed.
I live in Hudson, so public transit will never help me much. I used to live in University Heights, a suburb which grew up after the RTA lines were laid out. Ironically, I have been working in Chicago during the week for the past few months and have been getting by a combination of public transit and taxis. $150/mo parking in the condo complex where I am renting coupled with $20/day-ish downtown parking makes a $8 taxi ride a bargain (not to mention the $2.25 bus fare). It also helps that iGoCars (a non-profit zip car competitor) has stationed a car right outside my building.