Consultants are evil
To be honest: Most of my professional live I've been working as a software consultant. So I guess, I know what I'm talking about. I've always done my best to satisfy my customers, but after all it might not be the best option for my clients to hire me.
In my eyes consultants are modern soldiers. They work for every client who is paying them (well) so you can't be sure to get the same guys you hired last time when you need help later. Maybe business is some kind of combat, but it is much more complex than the art of (ancient) war. It takes you a lot of time and money to enable foreign guys to do any real work for you. You are telling them the secrets of your business and do pay them therefor. Remeber consultants are people who are complete out of your control!
For some strange reason hiring software engineers as consultants is much more common than any other engineers. I don't know why, but if software eats the world software is a very critical part of your business. You should definitely get this part under your control! I'm sure you got some contract to make sure the guys you hired are telling nobody else about your business, but can you really rely on that? Can you verify it? Remember they are soldiers, they work for you because you pay them.
Software consultants know nothing about your business. Most consulting companies offer you some kind of "business" or "software" consultant. To be honest, what you get is some more or less intelligent people with some technical background. In most cases these people have now knowledge about your business or even your industry! They are working for some manufacturer today, after they did a job at a telecommuication company before and before that maybe some ecommerce thing. Do you really think, this guys will help you to develp the future of your business? You are handling the core part of your company to someone who has no knowledge about what you are doing, do you really think this is a good idea?
Tranforming your business
The main reason you should not hire a consultant is, a consultant will bleed but he won't die for you. Meaning a consultant will do the things you pay him for and if he (or his company) doesn't fullfill the contract he will pay his dept, no more nor less. Although you might get some money (back) this doesn't help you.
Belive me, you need people who believe in your company! There is no longer a digital strategy, just a corporate strategy using digital tools. You'll need a team not an army of soldiers! It's the same reason contries and kings exchanged there army of soldiers to an national army at the end of the mediaval ages. Most sucessfull companys (and almost every startup) have realized teams make the difference. Only people who know your business, who live your ideas, can help you transform your company into the digital world. Make sure you get a team which is commited in your success not in your money.
Get rid of consultants. Hire your people for your business and you'll survive in the digital world!