Just wanted to pipe in with my own experience, but I've seen it come from the clients perspective too. Initial phase of the project is very visible and critical

Just wanted to pipe in with my own experience, but I've seen it come from the clients perspective too. Initial phase of the project is very visible and critical to the client and is delivered with the A-team. Client starts to care less as the bottom barrel of features start being implemented and they want to reduce costs. Instead of losing the contract, we start dropping some of the more expensive devs save for 1 or 2 very good ones to keep the project moving and we backfill with more junior to increase their experience. The client starts wanting to reduce the expense even more and we keep the 1 or 2 very good devs/architect and we bring on a few near-shore devs. Project coasts for a year or two until they're done with us or they have another high priority item that kicks the project into overdrive again.