Which is why the expected value of the loss without insurance is $2500.
You have a 5% chance of losing $50,000 and a 95% chance of losing nothing. If you have insurance with a $5000 deductible, that becomes a 5% chance of losing $5000 and and a 95% of losing nothing. Expected value is the sum over all events of (probability of event) times (cost of event). 5% times $5000 is $250, 95% times $0 is $0, total with insurance is $250 instead of $2500. So you risk $50,000 over $300 at 5% probability because $45,000 of the risk is on the insurance company.
You have a 5% chance of losing $50,000 and a 95% chance of losing nothing. If you have insurance with a $5000 deductible, that becomes a 5% chance of losing $5000 and and a 95% of losing nothing. Expected value is the sum over all events of (probability of event) times (cost of event). 5% times $5000 is $250, 95% times $0 is $0, total with insurance is $250 instead of $2500. So you risk $50,000 over $300 at 5% probability because $45,000 of the risk is on the insurance company.