It is impossible to predict what car competes with what other car, two years before either car hits the market. Car buying is mostly an emotional decision, more so than an economical or sensible one. Nothing is guaranteed based on product alone. When the Chevy Cruze was launched in 2010, it was miles ahead of the competition. Better economy, 6spd auto compared to 4spd auto in the Corolla/Civic and vastly superior fit and finish but that didn't affect how many Corolla/Civics were being sold. I have followed the midsize truck segment for several years as someone who owns one. Even though I own a Colorado, I will admit that the Nissan Frontier looks better, is several thousand cheaper, and is a much better value. Despite this the Chevy trucks handily outsell Nissan trucks.
The Bolt and Model 3 will not compete because the consumers buying them will not be the same. An Impala and BMW3 are in the same price range, neither is a bad car and they both do well sales wise. One group wants a soft riding full size sedan with a powerful motor while the other wants a nimble canyon carving RWD sports sedan. I wouldn't berate an Impala buyer for not buying a superb handling BMW, because what is important to me would not be what is important to someone else. Buying a $70,000 electric car may be one person's idea of going green while buying a $35,000 EV and spending $35,000 on solar panels for their house may be another person's idea of going green. They are both commendable and neither should be mocked for their choice.
The Bolt will be a compliance car but that doesn't mean it will be a bad one. The Volt and Spark EV are compliance cars too, both good cars (not great like the Model S) with very satisfied owners. Volt owners hate their car for four reasons, The low AER range, ICE backup, lack of DC fast charging capability and a 5th seat. The Bolt will address all four issues. It will not be a competition to the Model 3 and won't be as great, but it still has it's place. The Nissan leaf( and its Renault sibling) is by far the most popular EV globally. The Bolt will cost about the same, have twice the range with a liquid cooled battery. Since looks are subjective I will not comment on it.
The Bolt is a business decision. Two of the biggest auto markets(US and China) are rapidly embracing EVs, either due to policy reasons or changing consumer preferences. GM is the largest in one and the second largest in the other. 99% of their profit come from these two countries. GM will be dead in months without a competent EV if these two markets take to EVs in huge numbers. Everyone is wrong in assuming that GM and it's dealers are worried the Bolt will steal sales from ICE models. A Tahoe or Silverado buyer is not going to buy the Bolt. Bolt sales will either come from other non profitable cars or the competition. CAFE and CARB are two other reasons for GM and it's dealers to get very excited about selling EVs. You want to sell that Suburban with a $20K markup? Better move a few Bolts. One Bolt sold = 4 ZEV credits = $20,000 not paid in fines or $20,000 not paid to a competitor to buy credits.