Mostly because marginal pricing/merit order.

In a vast over simplfication, the most expensive producer that gets to supply sets the overall price. So even if you supply 99% from wind and hydro, the 1% of power that comes from gas sets the price for 100% of the electricity in the market.

When gas gets more expensive, electricity from gas gets more expensive. The more you have to rely on gas (because you don‘t have batteries, not enough solar, etc), the more you pay high prices.

There are different ways to address these issues. Demand side load management, batteries, etc.